Lenovo ThinkSystem SR635 Server

The Lenovo ThinkSystem SR635 is a 1-socket 1U server that features the AMD EPYC 7002 "Rome" and AMD EPYC 7003 "Milan" families of processors. With up to 64 cores per processor and support for the PCIe 4.0 standard for I/O, the SR635 offers the ultimate in single-socket server performance in a space-saving 1U form factor. With up to 128 PCIe lanes, the server is ideal for dense workloads that can take advantage of GPU processing and high-performance NVMe drives.

Suggested uses: AI Inference, VDI, OLTP, Analytics, HPC, software-defined storage

Figure 1. Lenovo ThinkSystem SR635

By using a high-performance server with only one processor installed, you can take advantage of lower software costs when the software licensing is using a per-socket model. In addition, The server offers onboard NVMe PCIe ports that allow direct connections to 16x NVMe SSDs, which frees up I/O slots and helps lower NVMe solution acquisition costs.

The SR635 has been designed to take advantage of the features of the EPYC 7002 and 7003 processors, such as the full performance of 280W 64-core processors, support for 3200 MHz memory and PCIe Gen 4.0 support. Competitive servers that are based on the older EPYC 7001 "Naples" designs may not be able to offer these performance features.

Combining performance and flexibility, the SR635 server is a great choice for enterprises of all sizes. The server offers a broad selection of drive and slot configurations and offers high performance features that industries such as finance, healthcare and telco need. Outstanding reliability, availability, and serviceability (RAS) and high-efficiency design can improve your business environment and can help save operational costs.

Scalability and performance

The SR635 offers numerous features to boost performance, improve scalability and reduce costs: 

• Supports the AMD EPYC 7002 and EPYC 7003 families family of processors
• Supports processors with up to 64 cores and 128 threads, core speeds of up to 4.1 GHz, and TDP ratings of up to 280W.
• Support for up to 16 TruDDR4 memory DIMMs, with 8 memory channels and 2 DIMMs per channel. With 1 DIMM installed per channel (8 DIMMs total), memory operates at up to 3200 MHz. With 2 DIMMs per channel (16 DIMMs total), memory operating at up to 2933 MHz.
• Using 128GB DIMMs, the server supports up to 2TB of system memory.
• Supports up to three single-width GPUs, each up to 75W. A 3:1 ratio of GPUs to CPUs means substantial processing power is available with just one CPU.
• Supports up to 16x 2.5-inch hot-swap drive bays, by using combinations of front-accessible (up to 10 bays), mid-accessible (4 bays), and rear-accessible (2 bays).
• Supports four 3.5-inch drive bays for lower-cost high-capacity storage. 2.5-inch and 3.5-inch drive bays can be mixed in several combinations.
• Supports 16x NVMe drives without oversubscription of PCIe lanes (1:1 connectivity) and without the need for additional NVMe adapters. The use of NVMe drives maximizes drive I/O performance, in terms of throughput, bandwidth, and latency.
• Supports 12x SATA drives using the onboard SATA controller (no additional adapter needed), enabling lower cost, high capacity storage solution for cold storage workloads.
• Supports 12x SAS drives using a variety of support RAID controllers or SAS HBAs.
• Supports high-speed RAID controllers from Broadcom providing 12 Gb SAS connectivity to the drive backplanes. A variety of RAID adapters are available, with cache and support for 16 drives on a single controller.
• Supports M.2 drives for convenient operating system boot functions or data storage. Available M.2 adapters support either one M.2 drive or two M.2 drives in a RAID 1 configuration for performance and reliability.
• The server has a dedicated industry-standard OCP 3.0 small form factor (SFF) slot, with a PCIe 4.0 x16 interface, supporting a variety of Ethernet network adapters. Simple-swap mechanism with thumbscrews and pull-tab enables tool-less installation and removal of the adapter. Supports shared BMC network sideband connectivity to enable out-of-band systems management.
• The server offers PCI Express 4.0 I/O expansion capabilities that doubles the theoretical maximum bandwidth of PCIe 3.0 (16GT/s in each direction for PCIe 4.0, compared to 8 GT/s with PCIe 3.0). A PCIe 4.0 x16 slot provides 64 GB/s bandwidth, enough to support a 400GbE network connection.
• A total of up to four PCIe 4.0 slots (3 with rear access, 1 internal for a RAID adapter) plus a slot dedicated to the OCP adapter.

Availability and serviceability

The SR635 provides many features to simplify serviceability and increase system uptime:

• The server uses ECC memory and supports memory RAS features including Single Device Data Correction (SDDC, also known as Chipkill), Patrol/Demand Scrubbing, DRAM Address Command Parity with Replay, and DRAM Uncorrected ECC Error Retry.
• The server offers hot-swap drives, supporting RAID redundancy for data protection and greater system uptime.
• The M.2 SATA RAID Boot Adapter supports RAID-1 which enables two installed M.2 drives to be configured as a redundant pair.
• The server has up to two hot-swap redundant power supplies and seven hot-swap redundant fans to provide availability for business-critical applications.
• The power-source-independent light path diagnostics uses LEDs to lead the technician to failed (or failing) components, which simplifies servicing, speeds up problem resolution, and helps improve system availability.
• Solid-state drives (SSDs) offer more reliability than traditional mechanical HDDs for greater uptime.
• The built-in ASPEED AST2500 baseboard management controller (BMC) continuously monitors system parameters, triggers alerts, and performs recovery actions in case of failures to minimize downtime.
• Proactive Platform Alerts: Voltage regulators, memory, fans, power supplies, server ambient and subcomponent temperatures. Alerts can be surfaced through the BMC to managers such as Lenovo XClarity Administrator. These proactive alerts let you take appropriate actions in advance of possible failure, thereby increasing server uptime and application availability.
• Web-based ThinkSystem System Manager (TSM) provides remote access to the BMC for remote management.
• Lenovo XClarity Provisioning Manager Lite (LXPM Lite) tool can be used to install an operating system on the server and perform system diagnostics.
• Three-year or one-year customer-replaceable unit and onsite limited warranty, 9 x 5 next business day. Optional service upgrades are available.

Manageability and security

Systems management features simplify local and remote management of the SR635:

• Supports Lenovo XClarity Provisioning Manager Lite (LXPM Lite) for system setup and firmware upgrades.
• An integrated industry-standard Unified Extensible Firmware Interface (UEFI) enables improved setup, configuration, and updates, and simplifies error handling.
• Support for industry standard management protocols, IPMI 2.0, SNMP 3.0, Redfish REST API, serial console via IPMI
• An integrated hardware Trusted Platform Module (TPM) supporting TPM 2.0 enables advanced cryptographic functionality, such as digital signatures and remote attestation.
• Administrator and power-on passwords help protect from unauthorized access to the server.
• Support for Lenovo XClarity Energy Manager, which captures real-time power and temperature data from the server and integrates with Redfish-based applications to provide automated controls to lower energy costs.
• Supports AMD Secure Root-of-Trust, Secure Run and Secure Move features to minimize potential attacks and protect data as the OS is booted, as applications are run and as applications are migrated from server to server.
• Supports Secure Boot to ensure only a digitally signed operating system can be used.
• Industry-standard Advanced Encryption Standard (AES) NI support for faster, stronger encryption.

• Energy-efficient planar components help lower operational costs.
• High-efficiency power supplies with 80 PLUS Platinum and Titanium certifications
• Low-voltage 1.2 V DDR4 memory offers energy savings compared to 1.35 V and 1.5 V DDR3 DIMMs.
• Solid-state drives (SSDs) consume as much as 80% less power than traditional spinning 2.5-inch HDDs.
• The server uses hexagonal ventilation holes, which can be grouped more densely than round holes, providing more efficient airflow through the system and thus keeping your system cooler.
• Optional Lenovo XClarity Energy Manager provides advanced data center power notification and analysis to help achieve lower heat output and reduced cooling needs.

The following figure shows the architectural block diagram of the SR635, showing the major components and their connections.

Figure 5. SR635 system architectural block diagram

The following table lists the standard specifications.

ThinkSystem SR635 models can be configured by using the Lenovo Data Center Solution Configurator (DCSC).

Configure-to-order (CTO) models are used to create models with factory-integrated server customizations. For CTO models, two types of base CTO models are available for the SR635 as listed in the columns in the following table:

• General purpose base CTO models are for general business (non-HPC) and is selectable by choosing General Purpose mode in DCSC.
• AI and HPC base models are intended for Artificial Intelligence (AI) and High Performance Computing (HPC) configurations and solutions are enabled using the AI & HPC Hardware - ThinkSystem Hardware mode in DCSC. These configurations, along with Lenovo EveryScale Solutions, can also be built using System x and Cluster Solutions Configurator (x-config). Tip: Some HPC and AI models are not listed in DCSC and can only be configured in x-config.

Preconfigured server models may also be available for the SR635, however these are region-specific; that is, each region may define their own server models, and not all server models are available in every region.

The following table lists the base CTO models of the ThinkSystem SR635 server.

Models of the SR635 are defined based on whether the server has 2.5-inch drive bays at the front (called the 10x 2.5" chassis or simply the 2.5-inch chassis) or whether it has 3.5-inch drive bays at the front (called the 4x 3.5" chassis or simply the 3.5-inch chassis). For models, the feature codes for these chassis bases are as listed in the following table.

The following tables list the available models, grouped by region.

• Models for Australia and New Zealand
• Models for South East Asian countries (ASEAN)
• Models for Brazil
• Models for EMEA countries
• Models for Hong Kong, Taiwan, Korea (HTK)
• Models for India
• Models for Japan
• Models for Latin American countries (except Brazil)
• Models for USA and Canada

Refer to the Specifications section for information about standard features of the server.

The SR635 supports processors in the AMD EPYC family of processors. The server supports one processor.

• Processor options
• Processor features
• UEFI operating modes

Processor options

The table below lists the supported AMD processors.

All supported processors have the following characteristics:

• Third and second-generation AMD EPYC processors (formerly codenamed "Milan" and "Rome" respectively)
• 7 nm process technology
• Eight DDR4 memory channels
• 128 PCIe 4.0 I/O lanes

Processor features

The following table lists the features of the supported processors.

The following table lists the features of the supported processors.

† The maximum single-core frequency at with the processor is capable of operating
* This processor supports 8 memory channels at 3200 MHz, however performance is optimized for 4 channels at 2666 MHz
** Processors with a P suffix are single-socket capable processors

The following table lists the feature codes that allow you to specify the mode you wish to preset in the factory for CTO orders.

The preset modes for the SR635 are as follows:

• Maximum Efficiency Mode (feature BFYA): Maximizes performance/watt efficiency while maintaining reasonable performance
• Maximum Performance Mode (feature BFYB): Achieves maximum performance but with higher power consumption and lower energy efficiency.

For details about these preset modes, and all other performance and power efficiency UEFI settings offered in the SR635, see the paper "Tuning UEFI Settings for Performance and Energy Efficiency on AMD Processor-Based ThinkSystem Servers", available from https://lenovopress.lenovo.com/lp1267.

The SR635 uses Lenovo TruDDR4 memory operating at up to 3200 MHz. The processors have 8 memory channels and support 2 DIMMs per channel, for a total of 16 DIMMs. The server supports up to 2TB of memory using 16x 128 GB 3DS RDIMMs.

The following table lists the memory options that are available for the server.

Lenovo TruDDR4 memory uses the highest quality components that are sourced from Tier 1 DRAM suppliers and only memory that meets the strict requirements of Lenovo is selected. It is compatibility tested and tuned to maximize performance and reliability. From a service and support standpoint, Lenovo TruDDR4 memory automatically assumes the system warranty, and Lenovo provides service and support worldwide.

The following rules apply when selecting the memory configuration:

• The 128GB 2933 MHz 3DS RDIMM, 4ZC7A15113, is only supported in the SR635 with an EPYC 7002 processor.
• The server supports RDIMMs and 3DS RDIMMs
• Mixing of RDIMMs and 3DS RDIMMs is not supported
• Mixing x4 and x8 DIMMs is supported, but not in the same channel
• Mixing of DIMM rank counts is supported. Follow the required installation order installing the DIMMs with the higher rank counts first.
• Mixing of DIMM capacities is supported, however only two different capacities are supported across all channels of the processor (eg 32GB and 64GB). Follow the required installation order installing the larger DIMMs first.
• Mixing of 3200 MHz and 2933 MHz DIMMs is supported. Installed memory will operate at the lower speed.
• Memory mirroring and memory rank sparing are not supported.
• When a GPU is added as a field upgrade, all empty DIMM slots must have a dummy DIMM blank installed in each DIMM slot, to ensure the optimal air flow. Ordering information is in the following table. For CTO orders, the dummy DIMMs are derived by the configurator.

The SR635 supports 4x 3.5-inch or 16x 2.5-inch drive bays or a combination of drive bays, depending on the selected chassis and backplane configuration. The server also supports configurations without any drive bays if desired.

All drives are hot-swap and are accessible from the front, from the rear, or from drive bays that are located in the middle of the server (accessible when you remove the top cover of the server).

The three drive bay zones are as follows:

• Front: 4x 3.5-inch hot-swap bays or up to 10x 2.5-inch hot-swap bays
• Mid (internal): 4x 2.5-inch hot-swap bays
• Rear: up to 2x 2.5-inch hot-swap bays

The server also supports one or two M.2 drives, installed in an M.2 adapter.

In this section:

• NVMe drive support
• Front drive bays
• Mid drive bays
• Rear drive bays
• Supported drive bay combinations
• Adapters selections
• Field upgrades
• M.2 drives

NVMe drive support

The SR635 supports NVMe drives to maximize storage performance. The server supports up to 16 NVMe drives without oversubscription (that is, each x4 drive has a full x4 connection (4 lanes) to the processor):

• 10x NVMe drives in the front bays
• 4x NVMe drives in the mid bays
• 2x NVMe drives in the rear bays

The specifics of these configurations plus other NVMe-rich configurations are covered in the Supported drive bay combinations and  Adapters selections sections.

The 10x NVMe drives at the front makes use of the 10-bay AnyBay backplane (feature B5VS) which requires SAS/SATA cabling and controllers as well as the NVMe cabling. However, if 16x NVMe drive bays are configured (ie all drive bays in the server populated with NVMe drives), then the server can be configured in the DCSC configurator without SAS/SATA cabling and controllers. Note that all 16x NVMe drive bays must be configured (using backplanes B5VS, B5VN and B5VQ); configurations of 10 or 12 or 14x NVMe drive bays will require SAS/SATA cabling and controllers.

These configurations are shown in the following figure.

Figure 6. SR635 front drive bay configurations

The backplanes used to provide these drive bays are listed in the following table.

* Backplanes are available as part numbers for field upgrades using upgrade kits, as described in the Field upgrades section below.
† AnyBay bays support SAS or SATA or NVMe drives; can also be configured as 10x NVMe drives without SAS/SATA cabling.

The backplanes used to provide these drive bays are listed in the following table.

* Backplanes are available as part numbers for field upgrades using upgrade kits, as described in the Field upgrades section below.

The use of drive bays in the mid-chassis area has the following configuration rules:

• Only NVMe drives are supported in the mid chassis area. SAS and SATA drives are not supported.
• The mid drive cage is only supported in conjunction with the 10x 2.5-inch AnyBay backplane (feature AUW9) or the 4x 3.5-inch SAS/SATA backplane (feature AUW8) for the front drives. The use of other front-drive backplanes with the mid cage is not supported.
• The mid drive cage occupies the same physical space as the M.2 module, internal PCIe slot (slot 4) and two of the three holders for RAID power module (supercaps). As a result, the M.2 module, slot 4 and two supercaps cannot be installed.

The backplanes used to provide these drive bays are listed in the following table.

* Backplanes are available as part numbers for field upgrades using upgrade kits, as described in the Field upgrades section below.

The use of rear drive bays has the following configuration rules:

• Slots 2 and 3 are not available
• Slot 1 is a low-profile slot
• GPUs are not supported

Supported drive bay combinations

This section describes the various combinations of 3.5-inch and 2.5-inch drives that the server supports. The drive bay combinations are grouped based on the drive type at the front of the server, 3.5-inch or 2.5-inch.

3.5-inch drive bay chassis

The following table shows the supported combinations when the server is configured with a 3.5-inch chassis (where the front drive bays are 3.5-inch). The choice of storage controller for each configuration is listed in the Adapter selections section.

2.5-inch drive bay chassis

The following table shows the supported combinations when the server is configured with a 2.5-inch chassis (where the front drive bays are 2.5-inch). The choice of storage controller for each configuration is listed in the Adapter selections section.

Adapter selections

The following tables lists the supported drive bay combinations plus the list of supported controller combinations supported by each of those drive bay combinations. Information about the controllers can be found in the Controllers for internal storage section.

* The configurations with 4 mid drives do not support the M.2 Module because the mid drive bays and the M.2 Module occupy the same physical space.

* These configurations, with 12 total SATA drives connected to the onboard SATA controller, or 4 mid drive bays, do not support the use of the M.2 Module. The M.2 Module and the onboard SATA bays use the same ports on the system board and the mid drive bays occupy the same space as the M.2 Module.

Field upgrades

This section describes the available upgrades to the storage subsystem.

• Backplane kits
• Cable kits for 440 HBAs and RAID 940 adapters
• Cable kit for Onboard SATA controller upgrades (X30 adapters only)
• RAID flash power module (supercap)

Backplane upgrades

The following table lists the option part numbers for the backplane kits that allow you to add additional drive bays as field upgrades. The table also lists what major components are included in each kit.

When adding drive bays, you will also need to add the appropriate storage controller(s). Consult the tables in the Adapter selections section to determine what controller sections are supported and what additional controllers you will need. Controllers are described in the Controllers for internal storage section.

† AnyBay bays support SAS or SATA or NVMe drives

Cable kits for 440 HBAs and RAID 940 adapters

The backplane kits listed in the preceding table include cables for use with the onboard SATA controller or with RAID 930, 730, 530 adapters and 430 HBAs (collectively called X30 adapters). If you wish to use the backplane kits with RAID 940 adapters or 440 HBAs (collectively called X40 adapters), then you will also need to order an additional X40 cable kit to use instead of the cables in the backplane kit.

Cable kit for Onboard SATA controller upgrades (X30 adapters only)

If your existing server is configured with drive backplanes that are connected to onboard SATA ports and you wish to upgrade to an X30 RAID adapter or SAS HBA (RAID 930, 730, 530 adapters and 430 HBAs), you will need to order the cable kit listed in the following table along with the adapter(s). The cable kit includes the additional cables you will need to connect the existing backplane to the new X30 adapter. Note that the kit includes the cables needed for all supported combinations of backplanes; this means that some of the cables in the kit will not be used.

For X40 RAID adapters and HBAs, instead order one of the X40 cable kits listed in the Cable kits for 440 HBAs and RAID 940 adapters section.

The cables in the kit are used with existing backplanes as listed in the following table.

RAID flash power module (supercap)

If you plan to add one of the RAID adapters that includes a RAID flash power module (supercap) as a field upgrade, then you will also need to order a Supercap installation kit for the power module. For CTO orders, the components in the installation kit are automatically derived when you select the RAID adapter. The adapters that this applies to are as follows:

• ThinkSystem RAID 730-8i 2GB Flash PCIe 12Gb Adapter
• ThinkSystem RAID 930-8i 2GB Flash PCIe 12Gb Adapter
• ThinkSystem RAID 930-16i 4GB Flash PCIe 12Gb Adapter
• ThinkSystem RAID 940-8i 4GB Flash PCIe Gen4 12Gb Adapter
• ThinkSystem RAID 940-16i 4GB Flash PCIe Gen4 12Gb Adapter

There are three possible locations for supercaps, as shown in the following figure.

Figure 9. Location of all three supercaps in the SR635

When adding a RAID adapter and supercap as a field upgrade, order the supercap installation kit list listed in the following table.

The following figure shows the use of the components of the option kit to install 1 or 2 supercaps. The third supercap is installed in location 3 in front of the cooling fans and behind the front operator panel as shown in the preceding figure (2.5-inch chassis only; not available with 3.5-inch front drives).

Figure 10. Supercap Installation Kit (locations 1 and 2)

Supported drives are listed in the Internal drive options section.

For further details about M.2 components, see the ThinkSystem M.2 Drives and M.2 Adapters product guide:
https://lenovopress.com/lp0769-thinksystem-m2-drives-adapters

The SR635 offers a variety of controller options for internal drives:

• Onboard SATA ports for up to 12 SATA drives
• RAID adapters and HBAs for SAS/SATA drives
• Onboard NVMe ports (for up to 16 NVMe drives)

The following table lists the adapters used for the internal storage of the server.

* The RAID 730-8i 1GB Cache adapter is not available in USA and Canada.

For a comparison of the functions of the supported storage adapters, see the ThinkSystem RAID Adapter and HBA Reference:
https://lenovopress.com/lp1288-thinksystem-raid-adapter-and-hba-reference#sr635-support=SR635

For more information about the adapters see the product guides in the RAID adapters or HBA sections of the Lenovo Press web site:
https://lenovopress.com/servers/options/raid
https://lenovopress.com/servers/options/hba

Configuration notes:

• Tri-Mode not supported: In the SR635, the Tri-Mode (Trimode) feature of the RAID 940-8i and 940-16i adapters (support for NVMe U.3 drives) is not supported.
• Field upgrades: If you are adding a RAID adapter to the SR635 as a field upgrade, you will need a Supercap Installation Kit as described in the Field upgrades section. For use of 940 RAID adapters or 440 HBAs, you will also need a cable kit. Take note of the configuration rules in that section.
• RAID 530-8i firmware: If you plan to use the RAID 530-8i in the SR655, it must have firmware 50.3.0-1032 or later applied before it can be used in the server. If the adapter you plan to use has older firmware (for example, you are using an adapter you previously purchased), it must first be upgrade by installing it in another server and upgrading the firmware there. For more information, see Support tip HT509177.

The following tables list the drive options for internal storage of the server.

The server does not supports any internal backup units, such as tape drives or RDX drives. External backup units are available as described in the External backup units section.

The server supports the external USB optical drive listed in the following table.

The drive is based on the Lenovo Slim DVD Burner DB65 drive and supports the following formats: DVD-RAM, DVD-RW, DVD+RW, DVD+R, DVD-R, DVD-ROM, DVD-R DL, CD-RW, CD-R, CD-ROM.

The server supports a total of up to 4 PCIe 4.0 slots (3 with rear access, 1 internal for a RAID adapter or HBA) plus a dedicated OCP 3.0 SFF slot for networking. Slot availability is based on riser selection.

• Slot 1: PCIe 4.0 x16 LP or FHHL
• Slot 2: PCIe 4.0 x16 LP (not present if slot 1 is FHHL or rear drive bays are present)
• Slot 3: PCIe 4.0 x16 LP (not present if rear drive bays are present)
• Slot 4: PCIe 4.0 x8 LP (internal slot; physically a x16 slot)

The following figure shows the locations of the rear-accessible slots for each configuration selection. The OCP slot in located in the lower-left corner.

Figure 11. SR635 slots

The slots and riser cards are as follows:

• Riser 1: Slot 1 (PCIe x16)
  • Slot 1: Low Profile or FHHL, PCIe 4.0 x16 slot
• Riser 2: Slots 2 & 3 (each PCIe x16)
  • Slot 2: Low Profile, PCIe 4.0 x16 (only available in 3x LP slot configuration)
  • Slot 3: Low Profile, PCIe 4.0 x16 (not available in configurations with rear drive bays)
• Internal Riser: Slot 4 (PCIe x8)
  • Low Profile PCIe 4.0 x8 slot for internal drive controller (physically a x16 slot)

The riser cards and slot brackets used to provide the above slot combinations in configure-to-order (CTO) configurations are listed in the following table.

Slot configurations can also be ordered as field upgrades using option part numbers, as listed in the following table.

The server has a dedicated OCP 3.0 SFF slot with PCIe 4.0 x16 host interface. See Figure 3 for the location of the OCP slot.

The following table lists the supported OCP adapters. One port can optionally be shared with the ASPEED management processor for Wake-on-LAN and NC-SI support. Only 1 OCP card can be installed in the server.

For more information, including the transceivers and cables that each adapter supports, see the list of Lenovo Press Product Guides in the Networking adapters category:
https://lenovopress.com/servers/options/ethernet

The following table lists additional supported network adapters that can be installed in the regular PCIe slots.

* Not supported in slot 2 when a 280W processor is installed
** See thermal requirements below
† In the SR635, this adapter requires a full-height bracket and must be installed in a full-height slot. The use of a low-profile bracket and slot is not supported.

The following thermal requirement apply to HDR/HDR100 InfiniBand and 100/200Gb Ethernet adapters:

• The high performance cooling fans must be installed. See the Cooling section for details.
• Ambient temperature cannot be greater than 35°C (if the processor TDP is 155W or lower) or 30°C (for 180W or higher processors)

For more information, including the transceivers and cables that each adapter supports, see the list of Lenovo Press Product Guides in the Networking adapters category:
https://lenovopress.com/servers/options/ethernet

The following table lists the Fibre Channel HBAs supported by the SR635.

Note that the Emulex LPe35000 adapters are supported either with EPYC 7002 "Rome" processors or with EPYC 7003 "Milan" processors, as indicated in the table.

For more information, see the list of Lenovo Press Product Guides in the Host bus adapters category:
https://lenovopress.com/servers/options/hba

The following table lists SAS HBAs and RAID adapters supported by SR635 server for use with external storage.

Configuration rules

The RAID 930-8e and RAID 940-8e use a flash power module (supercap), which can be installed in one of 3 locations as shown in the following figure.

Figure 12. Location of all three supercaps in the SR635 (2.5-inch drive configuration)

The number of supercap locations is reduced depending on installed components:

• For configurations with 2.5-inch front drives and no mid drive cage, 3x 930/940-8e adapters and supercaps can be installed (locations 1, 2, and 3).
• For configurations with 2.5-inch front drives and a mid drive cage installed, 1x 930/940-8e adapter and supercap can be installed (location 3 only).
• For configurations with 3.5-inch front drives, and no mid drive cage, 2x 930/940-8e adapters and supercaps can be installed (location 1 and 2; location 3 is not present).
• For configurations with 3.5-inch front drives and a mid drive cage installed, no 930/940-8e adapters and supercaps can be installed.
• If any internal RAID adapters with flash power modules are installed, the maximum number of 930/940-8e adapters supported is further reduced by that number.

For more information, see the list of Lenovo Press Product Guides in the Host bus adapters and RAID adapters categories:
https://lenovopress.com/servers/options/hba
https://lenovopress.com/servers/options/raid

The following table compares the specifications of the external SAS HBAs and RAID adapters.

* SAS HBAs support SEDs (self-encrypting drives) by using software on the server and simply passing SED commands through the HBA to the drives. SED support by RAID controllers is provided using the built-in MegaRAID SafeStore functionality of the adapter.

The SR635 supports the PCIe Flash Storage adapters listed in the following table.

For details about these adapters, see the Lenovo Press product guides in the Flash Adapters category:
https://lenovopress.com/servers/options/ssdadapter

Configuration rules

The following configuration requirements must be met when installing flash storage adapters:

• GPU adapters are not supported
• Maximum processor TDP is 155W
• Performance fans are required and will be derived by the configurator for configure-to-order builds.
• When adding Flash adapters as field upgrades, you will be required to replace all standard fans with performance fan modules. The ordering part number is listed in the following table - you will be required to order 7 fans.

The SR635 supports the following graphics processing units (GPUs).

For information about these GPUs, see the ThinkSystem GPU Summary, available at:
https://lenovopress.com/lp0768-thinksystem-thinkagile-gpu-summary

Configuration rules

The following configuration requirements must be met when installing GPUs:

• Some NVIDIA A Series GPUs are available as two feature codes, one with a CEC chip and one without a CEC chip (ones without the CEC chip have "w/o CEC" in the name). The CEC is a secondary Hardware Root of Trust (RoT) module that provides an additional layer of security, which can be used by customers who have high regulatory requirements or high security standards. NVIDIA uses a multi-layered security model and hence the protection offered by the primary Root of Trust embedded in the GPU is expected to be sufficient for most customers. The CEC defeatured products still offer Secure Boot, Secure Firmware Update, Firmware Rollback Protection, and In-Band Firmware Update Disable. Specifically, without the CEC chip, the GPU does not support Key Revocation or Firmware Attestation. CEC and non-CEC GPUs of the same type of GPU can be mixed in field upgrades.

• All GPUs installed must be identical
• Rear drive bays and mid-chassis drive bays are not supported.
• Flash storage adapters are not supported.
• 1100W power supplies (or in some configurations, 750W power supplies) are required.
• If the intrusion switch is installed, then only two GPUs can be installed, in slots 2 and 3. The intrusion switch and a GPU in slot 1 are mutually exclusive.

Additional rules when installing T4 GPUs:

• With two GPUs installed, processor TDP greater than 200W not supported
  • If ambient temperature is 35°C, then processor TDP greater than 120W not supported
  • If ambient temperature is 30°C, then processor TDP greater than 200W not supported
• With three GPUs installed, processor TDP greater than 120W not supported
• The following additional drive backplane rules apply if 3 GPUs are installed (rules do not apply if only 2 GPUs installed):
  • 3.5-inch drive bay backplane (AUW8) is fully supported
  • 8x 2.5-inch drive backplane (B7K3) supported, however 2 drive bays (6, 7) must be empty
  • 6x 2.5-inch SAS/SATA + 4x AnyBay backplane (AUW9) supported, however all AnyBay bays (6, 7, 8, 9) must be empty
  • 10x 2.5-inch AnyBay backplane (B5VS), however 4 bays (6, 7, 8, 9) must be empty
  • Ambient temperature great than 30°C is not supported
  • Processor TDP greater than 120W is not supported

Additional rules when installing any quantity of P620 GPUs:

• All front drive bay configurations are supported
• Ambient temperature great than 35°C is not supported
• Processor TDP greater than 240W is not supported

GPU field upgrades

When ordering GPUs as part of a CTO configuration, the necessary cooling features are automatically selected as part of the order. However when ordering the GPUs as field upgrades, you will need to also order 7 performance fans which will replace the standard fans already installed. 7 part numbers will need to be ordered per server.

When a GPU is added as a field upgrade, all empty DIMM slots must have a dummy DIMM blank installed in each DIMM slot, to ensure the optimal air flow. Ordering information is in the following table.

The SR635 server has seven 40 mm dual-rotor hot-swap variable-speed fans and either 6 or 7 fans are standard depending on the configuration. The fans are dual-rotor counter-rotating units, which means that the fans have two separate propellors, one in front of the other, and that the propellors rotate in opposite directions. The server offers N+1 redundancy. The server also has one additional fan integrated in each of the two power supplies.

Under all of the following conditions, only 6 fans are required:

• No M.2 Module
• No internal riser slot
• No mid drive bays
• No rear drives
• No GPUs

For all other configurations, all 7 fans are required.

Some configurations, such as the use of high-TDP processors, GPUs, flash storage adapters, mid drive or rear drives, or Ethernet/InfiniBand adapters of 100Gb or higher, will require the use of high performance fans which have higher RPMs. For configure-to-order builds, the DCSC configurator will automatically select the required fans. For field upgrades, the option part numbers may include the upgraded components when they are needed, or you may need to order the performance fans separately.

See these sections for details:

• Drive bay upgrade kits
• GPU upgrade kits
• Flash storage adapters
• PCIe network adapters

The server supports up to two redundant hot-swap power supplies.

The power supply choices are listed in the following table. Both power supplies used in server must be identical.

Dual-voltage power supplies are auto-sensing and support both 110V AC (100-127V 50/60 Hz) and 220V AC (200-240V 50/60 Hz) power. For China customers, all AC power supplies support 240V DC.

All supported AC power supplies have a C14 connector. The -48V DC power supply has a Positronic PLB3W3M1000/AA connector.

Power supply options do not include a line cord.

For server configurations, the inclusion of a power cord is model dependent. Configure-to-order models can be configured without power cords if desired.

For the -48V DC Power Supply, the following power cable is supported.

The server supports booting from an operating system or hypervisor installed on an M.2 solid-state drive. See the M.2 drives section for details and the list of available options.

You can download supported VMware vSphere hypervisor images from the following web page and load it on the M.2 drive using the instructions provided:
https://vmware.lenovo.com/content/custom_iso/

The server contains an integrated service processor which provides advanced control, monitoring, and alerting functions. The service processor is based on the ASPEED AST2500 baseboard management controller (BMC).

• Local management
• Remote management
• Lenovo XClarity Administrator
• Lenovo XClarity Provisioning Manager Lite
• Lenovo XClarity Essentials
• Lenovo XClarity Energy Manager