I've got 4 x 1gb geil 6400c ull memory here (2 x 2gb kits) which I had running at 800mhz @ 4-4-4-12 timings @ stock vdimm. I've since discovered that one of the 2gb kits reports timings as being 5-5-5-12 in cpu-z, whereas the other is 4-4-4-12 
Now they're identical part numbers, etc and I've tried both sets individually and in two rigs, which both have an e6400/ds3 installed and no matter what i do, the second set still shows up at 5-5-5-12 not 4-4-4-12!
Now tis is the condusing bit, I've run some benchies to check performance, and the results are near identical for both sets, in near identical rigs!
Also, the bios reports the timings as being 4-4-4-12 for both sets!
In fact, when I ran superpi, the set with the slacker reported timings was marginally quicker, reporting 19.5 @1 meg seconds, whereas the set with tighter timings was around the 20.5 seconds @ 1meg,
Any ideas?
Now they're identical part numbers, etc and I've tried both sets individually and in two rigs, which both have an e6400/ds3 installed and no matter what i do, the second set still shows up at 5-5-5-12 not 4-4-4-12!
Now tis is the condusing bit, I've run some benchies to check performance, and the results are near identical for both sets, in near identical rigs!
Also, the bios reports the timings as being 4-4-4-12 for both sets!
In fact, when I ran superpi, the set with the slacker reported timings was marginally quicker, reporting 19.5 @1 meg seconds, whereas the set with tighter timings was around the 20.5 seconds @ 1meg,
Any ideas?