Possible to use these B200-M4 memory sticks in B200-M3?

[mathew.goddard]

I'm about to have a bunch of these RAM sticks leftover from an M4 upgrade:

• 32GB DDR4-2133-MHz LRDIMM/PC4-17000/quad rank/x4/1.2v

Can I use these in an M3 blade that has E5-2600 v2 series CPUs?

The M3 spec sheet says it supports quad rank 32GB LRDIMMs of 1333, 1600 or 1866 MHz at voltages of 1.35 or 1.5V. So I'm wondering if those are hard limits or if it will accept these lower voltage, high frequency DIMMs and just throttle them back to 1866 MHz.

[Steven Tardy · Accepted solution]

You have:

 32GB DDR4-2133-MHz LRDIMM/PC4-17000/quad rank/x4/1.2v

The B200 M3 spec sheet:

https://www.cisco.com/c/dam/en/us/products/collateral/servers-unified-computing/ucs-b-series-blade-servers/B200M3_SpecSheet.pdf

Says:

DDR3 ECC registered DIMMs (RDIMMs) or load-reduced DIMMS (LRDIMMS)

DDR3 and DDR4 are physically (and electrically) incompatible.

[mathew.goddard]

Well spotted! I missed that.

Ah well, thanks anyway.