I have just had to replace 2 FBDIMMS in my D5400XS (skulltrail) system. The replacements sent were 4Gb FBDIMMS instead of 2Gb. So I now have a bank of 2 x 2Gb FBDIMMS and a bank of 2 x 4Gb FBDIMMS giving 12Gb in total.
It works fine, but my system performance seems to have dropped. I ran Everest to check things out and it says that the memeory controller is quad channel but the active mode is single channel. On benchmarks the write peformance is great (8184 MB/s) but read performance is at (3748MB/s). Although I remember read performance being sub par when I did the test 12 months ago, I don't remember it being this bad.
I have checked the BIOS and the timings are fine, the memoery is set to 400Mhz 1:1 and interleave is set.
Is this performance correct or has mixing the FBDIMM sizes caused the memery controller to drop from quad channel to single channel?
I guess thats OK But I always try to use the same size sticks in all slots it distributes the load more evenly. Bu the way what CPUs are you using , I'm waiting on a Xeon that I ordered ( X3380 ) I'm going to use it with a DX48BT2 , And see just what kind of clock speed I can get out of it . I've read some people have got into the 5.0os , It's going be a good project. Back to your prob. when I was using DDR2 I always used Gskill it is the most dependable . On your board do you have to use ECC ram or can you use std. ram ??
I have just found this article, so I have answered my own quesion and everything is OK. Thanks to those who replied.