X10SRi-F Slow Ram - running at 1867 not 2133

I have a X10SRi-F which I have been runing for a few years. I initially had 4x16 GB sticks @2133 but about a year ago I added another set of 4x16 @2133 to it, so all DIMM slots are now populated. I guess I never noticed, but this seems to have cut the speed down to 1867… Is that normal? Would a E5 2660 v4 not be able to run all chanels populed at 2133 mhz?

This is not really an “issue” as this is a homelab and the speed likely make absolutely no difference… but I was wondering if this was a known issue and something I can easily correct in BIOS (I coulnd’t find anything obvious), or if this is not normal behavior pointing to some other strange issue (server has been running perfectly fine for years, so I doubt anything is wrong).

Any ideas?

Yes, that is expected behaviour. Even official documentation says so (page 35).

Good rule of thumb is you will get advertised memory speeds when populating exactly 1 single rank memory module per channel.
You are populating 4+4x16 sticks, so you are running 2 dimms per channel. Your memory controller cannot handle that @ 2133MHz, hence dropdown to 1867.

Solution is obvious use less more dense memory modules :slight_smile:

I went looking for this info last night, but I stupidly didn’t even consider looking at supermicro’s documentation. I looked at intels and did some googling….

Thanks for pointing out my naivety haha.

Just glad it’s expected behavior. Like I said, the speed really doesn’t matter for my use case, I just wanted enough RAM for all the VM’s, one of which is truenas. I could have 100% made it work with 64GB, but for ~40 bucks I couldn’t say no to an extra 64GB