Update: Picked up the Corsair XMS3 6GB TR3X6G1600C9
Initially, when sticks went in, 4gb again. Then another cold boot, 6gb. Then every restart after that shows 6gb so far, without setting power/timings. Set the XMP profile. Tested the memory/system with Memtest, Occt, Prime95, 3dmark03, and Sisoftware Sandra. All results passed with no errors. This took about a full day and a half.
Then I tried to shutdown the computer and turned off the PSU. Waited a few minutes. Turned the PSU back on. And as soon as the light went on, on the mobo, I pressed the power button. And then upon boot, back to 4gb. Another cold boot would bring it back to 6gb.
So right now, it would seem like the situation is reversed.
With the OCZ golds, I would get 6gb sometimes on initial cold boots, with and without setting timings. And then restarts would ALWAYS show 4gb again. And of course, memtest saw 6gb but had errors.
With the Corsairs, I would now get 6gb about 70% of the time upon cold boots and once bios/windows sees 6gb, restarts always show 6gb. And when I turn off the PSU and then back on, then power on right after, it would be 4gb. But if I wait a few minutes first, after I've turned the PSU back on, then power on, 70% of the time it would be 6gb. Also, turning off the computer at night, then powering it on the next morning would show 4gb, but a second cold boot would bring it back to 6gb again.
So I tried setting the voltage. Dimm: 1.7 (from 1.65) QPI: 1.4 (from 1.35) I know Intel specs say anything more than 1.65 might damage the integrated memory controller, but I've seen people post much higher voltages than these. I hope that it would be fine. Tested this for about 10 hours. Cold boots, restarts, and turning on/off PSU would yield 6gb all the time, at least that I can remember. There's been so many tests. So basically at this point, I'm feeling pretty confident with the system.
Woke up this morning, boot up the computer, back to 4gb. Windows locked up. Another cold boot, and back to 6gb. Haven't tested it more after that yet. So right now, I'm guessing that the system is 'pretty' stable, except sometimes from cold boots it would have trouble powering the 6gbs maybe?
So a definite improvement with the Corsairs. At this point, with all the testing, should I still be thinking about changing any hardware? (Haven't changed the CPU or PSU) Is this occurrence which happens much less often now, normal/expected/tolerable? I assume I can increase the voltages more.
The RMA window is closing in. Thoughts and suggestions please. Thanks.