Lenovo ThinkSystem SR655

Lenovo's single-socket 2U rack server (machine types 7Y00/7Z01) 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 32 x 2.5-inch or 20 x 3.5-inch drives, eight rear PCIe 4.0 slots plus an OCP 3.0 slot and room for double-wide GPUs. Aimed at storage-rich, NVMe, VDI and GPU inference workloads; it can also be ordered as a rack workstation for Windows 10/11.

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; with a 2666 MHz-bus processor all DIMMs run at 2666 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, 16 or 24 x 2.5" SAS/SATA or NVMe from 8-bay backplanes (e.g. 8 NVMe + 16 SAS/SATA); or no backplane
Front 3.5": 8 or 12 x 3.5" SAS/SATA, or 8 x SAS/SATA + 4 x AnyBay (bays 8-11; no PCIe 4.0 NVMe drives)
Mid: 4 x 3.5" SAS/SATA, or 8 x 2.5" SAS/SATA or NVMe (NVMe via PCIe switch); max 155 W CPU, no GPUs or full-length cards
Rear: 4 x 3.5" SAS/SATA, 4 x 2.5" SAS/SATA or 4 x 2.5" NVMe (NVMe via PCIe switch)
Maximum: 32 x 2.5" (36 physical bays; 2.5" mid and rear are mutually exclusive) or 20 x 3.5"; 28 NVMe direct-attached or 32 NVMe at 2:1 oversubscription
Controllers: Onboard SATA (up to 16 drives, no RAID), onboard NVMe (up to 16 drives), RAID 530-8i, 540-8i, 730-8i, 930-8i/16i/24i, 940-8i/16i/32i (no Tri-Mode), HBA 430-8i/16i, 440-8i/16i; 4-port NVMe retimer and 810-4P/1610-4P/1611-8P NVMe switch adapters for 20+ NVMe drives
Internal slot: Slot 9: 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; needs performance fans
Optical: None internal; external USB DVD-RW option

Graphics

Onboard: ASPEED AST2500 BMC graphics, max 1920x1200 at 60 Hz
Double-wide: NVIDIA A100 40/80GB, A40 48GB, A30 24GB, Tesla V100 16/32GB, V100S 32GB, AMD Instinct MI210 (EPYC 7003 only); RTX A6000, RTX A4500 and RTX A2000 only on Windows 10/11 orders; up to 2 per the GPU table (slots 1 and 7), though the guide's thermal table also lists 3-GPU configurations
Single-wide: NVIDIA A2 16GB, T4 16GB, Quadro P620 2GB, up to 6 (slots 1, 2, 4, 5, 7, 8); 8 x T4 by special bid
Rules: All GPUs identical; double-wide GPUs block the adjacent slot; with double-wide or T4 GPUs max 8 x 3.5" or 16 x 2.5" front bays, no mid/rear drives, no flash adapters; 1600 W (sometimes 1100 W) PSUs; high-performance (controlled) GPUs only on the "for AI" base models

Expansion

Riser 1: Slots 1-3, full height (full length, or half length with mid drives): x16/x8/x8, x16/x16, x16 in slot 1 only, or slot 3 only (with 3.5" rear bays)
Riser 2: Slots 4-6: x16/x8/x8 (slots 4-5 full-height full-length or low profile, slot 6 low profile), x16/x16, or slot 6 only (with 3.5" rear bays)
Riser 3: Slots 7-8, full height: x8/x8 or x16/x16 (not with rear drive bays)
Slot 9: 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: 8 rear slots; 6 slots + 4 x 2.5" rear drives; 2 slots + 4 x 3.5" 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 (incl. AMD X3522 low latency), 100 GbE (Broadcom 57508, ConnectX-6 Dx), InfiniBand HDR100/HDR (ConnectX-6)
Fibre Channel: Emulex LPe36002 64Gb, LPe35000/35002 32Gb (v1 with EPYC 7002, v2 with EPYC 7003), QLogic QLE2770/2772/2740/2742 32Gb, 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), 1600 W Platinum (230 V), 750 W Titanium (230 V), 1100 W -48 V DC (special bid); Lenovo Docs' spec table also lists a 2000 W Platinum (230 V) unit that the product guide's option table does not
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, 1600 W 8.7 A
Heat output: 123 W (421 BTU/hr) minimum to 1643 W (5606 BTU/hr) maximum configuration
Cooling: 6 hot-swap 60 mm single-rotor fans (5 in simple configurations), N+1; standard or performance (29,000 RPM) fan modules; one fan in each PSU

Ports

Front: 2 x USB 3.2 Gen 1 (5 Gbps), optional VGA on the left rack latch (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: 2U rack
Dimensions: 445 mm W x 87 mm H x 764 mm D (17.5 x 3.4 x 30.1 in); 482 mm across the rack flanges
Weight: Maximum 35.4 kg (78.0 lb)
Machine types: 7Y00 (1-year warranty), 7Z01 (3-year warranty); 7Z01CTO2WW / 7Y00CTO2WW Workstation base models for Windows 10/11
Environment: ASHRAE A2 (10-35 C); some 280 W, GPU and 24 NVMe + 8 mid configurations limited to 30 C; A3/A4 only for restricted configurations (155 W max CPU, no NVMe, GPUs or 10 GbE+)
Acoustics: Typical 6.2 Bel / 47 dBA operating; GPU-rich up to 8.5 Bel / 69 dBA
Rails: Toolless slide rail (optional 2U 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; Windows 10 (x64) and Windows 11 on the SR655 Workstation base models, with a restricted adapter and drive list
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