How many GPUs does the Lenovo ThinkSystem SR650a V4 support?
Up to eight single-wide or four double-wide GPUs, all in the eight front PCIe 5.0 slots. Only the NVIDIA L4 reaches eight; the RTX PRO 4500 and L40S stop at four, and 600 W cards (H200 NVL and RTX PRO 6000 at full power) are limited to two, in slots 21 and 23.
Which GPUs can be fitted in the SR650a V4?
Lenovo’s table lists the NVIDIA L4 24 GB, RTX PRO 4500 Blackwell 32 GB, L40S 48 GB, 96 GB RTX PRO 6000 Blackwell (full 600 W or a 450 W cap) and H200 NVL 141 GB — all passively cooled. H200 NVL pairs can take one optional two-way NVLink bridge. Every card is marked as controlled, meaning it is not offered in certain markets.
What does a 600 W GPU configuration need?
Two 600 W front risers for slots 21 and 23, the 600 W riser cages and double-wide air duct, and 24K Ultra fan modules — five with one processor, six with two. For a field upgrade Lenovo lists a fan kit, a mechanical kit carrying the cages and duct, one riser per GPU, and GPU power cables.
Can the SR650a V4 run four RTX PRO 6000 Blackwell GPUs?
Yes, in the power-capped configuration (feature CHWT): four cards at 450 W in slots 17, 19, 21 and 23. At the full 600 W the limit is two. Lenovo supports converting between the two layouts in the field with the matching risers, cables and fans, and firmware sets the GPU power at boot.
What is the maximum memory of the SR650a V4?
8 TB, using 32 × 256 GB 3DS RDIMMs across two processors. RDIMM speed is 6400 MT/s at one per channel, dropping to 5200 MT/s at two, while five processors can use 64 GB MRDIMMs at 8000 MT/s, one per channel. One processor leaves 16 slots.
Which processors does the SR650a V4 take?
One or two of 27 Intel Xeon 6 P-core processors from the 6500 and 6700 series, from the 8-core 6503P to the 86-core 6787P, rated 135 W to 350 W. Six of them — 6511P, 6521P, 6731P, 6741P, 6761P and 6781P — are single-socket only and cannot be added later.
How many drive bays does the SR650a V4 have?
Eight at the front: 2.5-inch SAS/SATA, AnyBay or NVMe, or E3.S 1T NVMe on two four-bay backplanes. There are no 3.5-inch, mid-chassis or rear bays, and up to two M.2 boot drives sit internally, in a rear hot-swap cage, or in a front cage with E3.S drives.
What power supplies and cooling does the SR650a V4 use?
Up to two identical hot-swap supplies from 800 W to 3200 W, with the 2000 W and larger units needing 230 V; HVAC/HVDC and –48 V DC options exist too. Fan type rises with GPU power, from Performance fans for cards up to 400 W to 24K Ultra fans at 600 W, and the processors can be water-cooled on an open loop.
How is the SR650a V4 different from the SR650i V4 and SR650 V4?
The SR650i V4 is one fixed SR650a V4 build for inference, with two RTX PRO 6000 GPUs and set processors, memory and drives; the SR650a V4 is the open, configure-to-order platform. The SR650 V4 is the 2U sibling that, by this guide’s account, keeps the 3.5-inch, E3.S 2T, mid-chassis and rear bays the SR650a V4 gives up for front GPUs.
Is the Lenovo SR650a V4 end of life?
Lenovo’s product guide of 27 August 2026 presents the SR650a V4 as a current platform and gives no end-of-service date. Support terms depend on the warranty or service contract on each server; our end-of-life checker will show dates once Lenovo publishes them.
