Originally Posted by
Slammin
If you've ever run that memory at a speed and vdimm that caused it to get too warm, it will 'change' characteristics. Those chips are rated at like 2.2 - 2.4v I think, and though they may post with 1.8v, chances of them continuing to post at 1.8v diminish thelonger you run them at higher speed and vdimm. There's two good threads detailing this on those chips in the Extreme Bandwidth section.
Out of my 4 sticks, all of which could post at 1.8v when I first bought them, only 1 can now. I sent one pair back for RMA, and out of the pair I got back, only one of those would post at 1.8v. Now neither of them do.
The ram is not defective though. It's just different from when I first got it.