Hey I'm suffering from very weird memory problems:

It started yesterday when I got BSOD's all day long. My system is Opteron [email protected], DFI Ultra-D and my ram is Corsair 3200C2 rev 1.5 (BH5 UTT). Since yesterday, they were happy running at 258mhz@[email protected] - in fact, I've been running this overclock 24/7 for the past month no probs.

I ran memtest (skipped to test 5) and it gave me thousands of errors.

I then tried my friend's 3500C2 rev 1v1 (old BH5) at the same speeds, and it passed both Memtest and Superpi 32M. I have no idea what's wrong with my ram, since it running fine they day before at the same settings, so I presumed I just fried it or something.

So I tested each stick individually, using memtest test 5, at the same settings. Neither gave me errors.

I put it in dual channel, and blam, thousands of errors.

At this point, I'm thinking it's because of slot 3 on my mobo, so I switched the ram to slots 2 and 4, and ram memtest. It returned no errors for 5 iterations (of test 5).

Then I boot into windows, and ran superpi, despite passing memtest, superpi 32M did not complete 1 loop.

I then dropped the divider and the ram was 236mhz. No memtest test 5 errors, but Superpi 32M passed 3 loops only.

So from my diagnosis, it is definitely the RAM at fault, but I can't figure out for the life of me what's causing these errors:
1. no errors in single stick but errors in dual channel
2. no errors in slots 2 and 4 but errors in slots 1 and 3
3. no memtest errors but superpi doesn't pass 1 loop. (note: I know my cpu is perfectly capable of that. I tested it at the same settings with my friend's ram and it passed)

Any help on this subject will be greatly appreciated. I still don't know whether the ram itself got fried and I should RMA them.

Errors in dual channel sounds like a CPU memory controller problem. I'll let someone more knowledgeable give you more guaranteed advice.