4X77A83756: Lenovo ThinkSystem 32GB TruDDR4 3200MHz (2Rx4 1.2V) RDIMM

Also listed as: 4X77A83756-01, 02DA218, M393A4K40EB3-CWE, SP47A83756, B8J5 · made by Samsung

The Lenovo 4X77A83756 is a 32GB dual-rank (2Rx4) TruDDR4 registered memory module operating at 3200MHz with 1.2V power consumption. It is engineered with proprietary Lenovo TruDDR4 signature memory technology, allowing the system UEFI to verify genuine modules, unlock fine-tuned timing profiles, and log detailed memory health analytics. Heavily traded across 3rd Generation Intel Xeon Scalable (Ice Lake) ThinkSystem and ThinkServer deployments, it is standard equipment for virtualization hosts and database nodes. Used buyers should verify the Lenovo security label on the heat spreader to avoid re-flashed generic modules.

Specifications

About the 4X77A83756

4X77A83756 is Lenovo's ultra-high-density 128GB 4Rx4 3D-stacked (3DS) TruDDR5 registered ECC memory module designed for maximum memory capacity deployments in ThinkSystem V3 servers. Utilizing through-silicon via (TSV) stacking technology, it enables multi-terabyte system configurations for large language model inference caching, large-scale virtualization nodes, and in-memory analytics. Within Lenovo's lineup, it represents the high-water mark for 4800MHz memory density before moving to specialized 256GB modules.

Compatibility

The 128GB 3DS module is supported on Lenovo ThinkSystem SR650 V3, SR630 V3, SR665 V3, SR645 V3, and SR850 V3 servers running compatible processor tiers. It requires Intel Xeon Platinum/Gold 4th Gen or AMD EPYC 9004 processors capable of driving high-density 3DS modules. It cannot be mixed with standard non-3DS RDIMMs (such as 32GB or 64GB modules) within the same server. Servers must have current UEFI firmware applied to ensure correct 3DS rank timing and power distribution.

How to identify a genuine unit

The module features a distinctive Lenovo factory label with option part number 4X77A83756, FRU number SP47A83756, and feature code BQ6B. Due to 3DS TSV packaging, the DRAM chips are noticeably taller than standard planar chips. In the Lenovo XClarity interface, the module identifies as 128GB 4Rx4 3DS TruDDR5. Generic third-party modules without the Lenovo TruDDR5 signature will flag an unsupported memory warning and disable vendor-tuned operating modes.

Buying used

Due to the high cost of 128GB modules, test every stick extensively using Lenovo Dynamic System Analysis (DSA) or MemTest86 for several passes. Inspect the TSV stacked DRAM dies under magnification for micro-cracks or chipped packaging caused by improper socket extraction. Verify that thermal sensors report consistent temperatures across all modules under load. Insist on purchasing matched manufacturing date batches when populating across memory channels.

Reference prices (last 14 days, updated 2026-10-27)

Prices seen on public listings on the dates shown, before tax and shipping. Not an offer.

Fits these models

• Lenovo ThinkSystem SR650 V2
• Lenovo ThinkServer SR660 V2
• Lenovo ThinkAgile VX650 V2
• Lenovo ThinkSystem SD650 V2
• Lenovo ThinkSystem SE450
• Lenovo ThinkSystem SR630 V2
• Lenovo ThinkSystem SR645
• Lenovo ThinkSystem SR650
• Lenovo ThinkSystem SR665
• Lenovo ThinkSystem SR670 V2
• Lenovo ThinkSystem SR850 V2
• Lenovo ThinkSystem SR860 V2
• Lenovo ThinkSystem ST650 V2

Equivalent part numbers

• Dell AA579532 Dell 32GB 2Rx4 DDR4-3200 RDIMM
• HPE P06033-B21 HPE 32GB 2Rx4 DDR4-3200 RDIMM

FAQ

Sources

• Lenovo ThinkSystem SR650 V2 Server Product Guide - Memory Options, checked 2026-10-27