Lenovo ThinkSystem SR635

Lenovo's single-socket 1U rack server (machine types 7Y98/7Y99) for one AMD EPYC 7002 "Rome" or 7003 "Milan" processor up to 64 cores and 280 W, with 16 DDR4-3200 DIMM slots (up to 2 TB), up to 16 x 2.5-inch drives (up to 16 NVMe with direct connections) or 4 x 3.5-inch, three rear PCIe 4.0 slots and an OCP 3.0 slot. Aimed at dense NVMe, VDI, inference and software-defined storage nodes where per-socket licensing matters.

Memory

Slots: 16 DIMM (8 channels, 2 DIMMs per channel)
Types: Lenovo TruDDR4 RDIMM 8, 16, 32, 64 GB and 3DS RDIMM 128 GB, 2933 MHz or 3200 MHz; RDIMM and 3DS RDIMM cannot be mixed; no persistent memory
Speed: 3200 MHz DIMMs run at 3200 MHz at 1 DPC and 2933 MHz at 2 DPC; 2933 MHz DIMMs run at 2933 MHz
Max: 2 TB (16 x 128 GB 3DS RDIMM); minimum 8 GB
Population: For best performance populate 8 or 16 DIMMs so all channels are used; x4 and x8 DIMMs cannot share a channel; at most two DIMM capacities
Protection: ECC, SDDC (x4 DIMMs), patrol/demand scrubbing, DRAM address/command parity with replay, uncorrected ECC error retry, Post Package Repair; no mirroring or rank sparing

Storage

Front 2.5": 8 x SAS/SATA, 6 x SAS/SATA + 4 x AnyBay, or 10 x AnyBay (usable as 10 x NVMe without SAS cabling); or no backplane
Front 3.5": 4 x 3.5" SAS/SATA hot-swap
Mid: 4 x 2.5" hot-swap NVMe (7 mm drives only) under the top cover; only with the 4 x 3.5" or 10-bay 2.5" front backplanes
Rear: 2 x 2.5" hot-swap SAS/SATA or 2 x NVMe (7 mm NVMe only)
Maximum: 16 x 2.5" (10 front + 4 mid + 2 rear), up to 16 NVMe with direct x4 connections; 12 SAS/SATA drives
Controllers: Onboard SATA (up to 12 drives, no RAID), onboard NVMe (up to 16 drives), RAID 530-8i, 540-8i, 730-8i 1/2 GB, 930-8i/16i, 940-8i/16i (no Tri-Mode), HBA 430-8i/16i, 440-8i/16i
Internal slot: Slot 4: internal PCIe 4.0 x8 riser for a RAID adapter or HBA
M.2 boot: M.2 module for 1 or 2 drives: SATA RAID kit (Marvell 88SE9230, RAID 0/1) or SATA/NVMe kit (JBOD); 2242/2260/2280
Optical: None internal; external USB DVD-RW option

Graphics

Onboard: ASPEED AST2500 BMC graphics, max 1920x1200 at 60 Hz
GPU options: NVIDIA A2 16GB, T4 16GB, Quadro P620 2GB, up to 3 (slots 1-3)
Rules: All GPUs identical; no rear or mid drive bays; no flash adapters; 1100 W (or sometimes 750 W) PSUs; with the intrusion switch only slots 2-3; T4: 2 GPUs max 200 W CPU, 3 GPUs max 120 W CPU and 30 C; P620: CPU max 240 W

Expansion

Slot 1: PCIe 4.0 x16, low profile or full-height half-length (riser 1)
Slot 2: PCIe 4.0 x16, low profile (riser 2; only in the 3 x LP layout)
Slot 3: PCIe 4.0 x16, low profile (riser 2; not with rear drive bays)
Slot 4: Internal PCIe 4.0 x8 low profile (physically x16) for a storage controller
OCP: Dedicated OCP 3.0 SFF slot, PCIe 4.0 x16
Slot layouts: 3 x LP; 1 x FHHL + 1 x LP; 1 x LP + 2 x 2.5" rear drives

Networking

OCP 3.0: Optional 2- or 4-port adapters: 1 GbE (Broadcom 5719, Intel I350), 10GBASE-T (Broadcom 57416/57454, Intel X710-T2L/T4L, Marvell QL41132), 10/25 GbE SFP28 (Broadcom 57414/57454/57504, Intel E810-DA2/DA4, Mellanox ConnectX-4 Lx/ConnectX-6 Lx, Marvell QL41232); one port can be shared with the BMC
PCIe: 1/10/25 GbE, 100 GbE (Broadcom 57508, ConnectX-6 Dx), InfiniBand HDR100/HDR (ConnectX-6); 100/200 Gb adapters need performance fans
Fibre Channel: Emulex LPe35000/35002 32Gb (v1 with EPYC 7002, v2 with EPYC 7003), QLogic QLE2770/2772/2740/2742 32Gb, Emulex and QLogic 16Gb HBAs
Management: 1 x RJ-45 1 GbE BMC port

Power

PSU options: 550 W, 750 W and 1100 W Platinum (115/230 V), 750 W Titanium (230 V), 1100 W -48 V DC (special bid)
Redundancy: 1 or 2 hot-swap PSUs; both must be identical
Connector: C14 inlets on AC units; Positronic connector on the -48 V DC unit; 240 V DC input in China only
Input current: 100-127 V: 550 W 6.2 A, 750 W 8.4 A, 1100 W 12 A; 200-240 V: 550 W 3.0 A, 750 W 4.1 A, 1100 W 6 A
Heat output: 101 W (346 BTU/hr) minimum to 937 W (3197 BTU/hr) maximum configuration
Cooling: 7 hot-swap 40 mm dual-rotor fans (6 when there is no M.2, internal slot, mid/rear drives or GPU), N+1; standard or performance fan modules; one fan in each PSU

Ports

Front: 2 x USB 3.2 Gen 1 (5 Gbps), optional VGA (disables rear VGA when used)
Rear: 2 x USB 3.2 Gen 1, 1 x VGA, 1 x DB-9 serial, 1 x RJ-45 BMC management, NMI button

Physical

Form factor: 1U rack
Dimensions: 440 mm W x 43 mm H x 755 mm D (17.3 x 1.7 x 29.7 in); 482 mm across the rack flanges; Lenovo Docs gives 778.3 mm depth with latches and PSUs
Weight: Maximum 19.2 kg (42.3 lb)
Machine types: 7Y98 (1-year warranty), 7Y99 (3-year warranty)
Environment: ASHRAE A2 (10-35 C); 225 W+ CPUs, mid/rear drives and 3 GPUs limit ambient to 30 C; A3/A4 only for restricted configurations (155 W max CPU, no NVMe, GPUs or 10 GbE+)
Acoustics: Typical 5.9 Bel / 43 dBA operating; GPU-rich up to 8.5 Bel / 69 dBA
Rails: Toolless slide rail (optional 1U CMA) or toolless friction rail v2; 610-864 mm between rack posts

Management

BMC: ASPEED AST2500 baseboard management controller with web-based ThinkSystem System Manager (TSM); remote KVM (up to 1920x1080) and virtual media are standard
Interfaces: IPMI 2.0 (IPMI-over-LAN disabled by default), SNMPv3, Redfish, HTML5 web UI; dedicated 1 GbE management port or NC-SI sharing (10/100 Mb) on OCP adapter port 1
Software: XClarity Provisioning Manager Lite (LXPM Lite), XClarity Administrator, XClarity Essentials, XClarity Energy Manager, Capacity Planner
Security: TPM 2.0 (Nationz TPM 2.0 in China, CTO only), NIST SP 800-147B, Secure Boot, AMD Secure Root-of-Trust, optional intrusion switch (CTO only) and lockable front bezel, power-on and administrator passwords
Local: Front operator panel, pull-out network information tab, light path fault LEDs for DIMMs, drives, fans and PSUs
Announced: Product guide first published 2019-08-07
Withdrawn: Withdrawn from marketing (Lenovo Press update of 2025-03-12)

Operating systems

Windows: Windows Server 2016, 2019, 2022
Linux: RHEL 7.6-7.9 (EPYC 7002 only), 8.0-8.10 (8.3 and later with EPYC 7003), 9.0-9.8; SLES 12 SP4 (7002 only) and SP5, 15 SP1 (7002 only) to SP7; Ubuntu 22.04 and 24.04 LTS
VMware: ESXi 6.5 U3 (EPYC 7002 only), 6.7 U3, 7.0 and 7.0 U1 (EPYC 7002 only), 7.0 U2, 7.0 U3, 8.0 through 8.0 U3; factory ESXi preload available (not with NVIDIA GPUs)

Processors

AMD EPYC 7203
AMD EPYC 7203P
AMD EPYC 72F3
AMD EPYC 7303
AMD EPYC 7303P
AMD EPYC 7313
AMD EPYC 7313P
AMD EPYC 7343
AMD EPYC 73F3
AMD EPYC 7413
AMD EPYC 7443
AMD EPYC 7443P
AMD EPYC 7453
AMD EPYC 74F3
AMD EPYC 7513
AMD EPYC 7543
AMD EPYC 7543P
AMD EPYC 75F3
AMD EPYC 7643
AMD EPYC 7643P
AMD EPYC 7663
AMD EPYC 7663P
AMD EPYC 7713
AMD EPYC 7713P
AMD EPYC 7763
AMD EPYC 7232P
AMD EPYC 7252
AMD EPYC 7262
AMD EPYC 7F32
AMD EPYC 7272
AMD EPYC 7282
AMD EPYC 7302
AMD EPYC 7302P
AMD EPYC 7F52
AMD EPYC 7352
AMD EPYC 7402
AMD EPYC 7402P
AMD EPYC 7F72
AMD EPYC 7452
AMD EPYC 7502
AMD EPYC 7502P
AMD EPYC 7532
AMD EPYC 7542
AMD EPYC 7552
AMD EPYC 7642
AMD EPYC 7662
AMD EPYC 7702
AMD EPYC 7702P
AMD EPYC 7742
AMD EPYC 7H12