8GB FB-DIMMS - compatible chipsets, Supermicro X7 boards?


Active Member
May 6, 2015
SF Bay area
Greetings all,

I'm trying to max out some older FB-DIMM based systems with cheap RAM - a friend's first generation mac pro, and several Supermicro x7 boards I have on hand.

The Supermicro boards (X7DBE for example) have 8-16 DDR2 FB-DIMM slots, but the specs list the largest compatible FB-DIMM as 4GB. Does anyone know of any which either:
  1. are rated for 8GB FB-DIMMS
  2. work with 8GB FB-DIMMS despite specs stating 4GB max
  3. work with 8GB FB-DIMMs despite specs, but only up to the same total capacity the board is rated for with 4GB FB-DIMMS? (for example, if a board with 16 RAM slots is rated at 64GB max with 4GB FB-DIMMs, you can actually use 8x 8GB, but any more RAM will cause boot failure)
Reading up on 8GB FB-DIMMS (most seem to be 2Rx4) the few customer reviews I have found of them mention compatibility problems, even with systems which are supposedly rated for them, such as some HP G5 DL series.

Has anyone had any luck, or are 8GB FB-DIMMs to be avoided?



Jun 23, 2016
I have two Intel S5000PSL boards here which officially support 32 GB with their 8 FB-DIMM slots (manual: https://www.intel.com/content/dam/s...ds/server/sb/d36217006_s5000psl_userguide.pdf). However, I can successfully use 8x 8 GB DIMMs for 64 GB with them. But with this configuration, the boards are very picky about the install order of the FB-DIMMs - finding a combination (DIMM to slots) that will allow the board to post wasn't easy. When I use only 4 of these 8GB DIMMs, it isn't a problem.

So you may have a chance to put 8 of these modules in your boards.
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