Memtest passes but Vista won't boot

mwtb · 26 Mar 2007 at 21:00

I have a curious problem, likely leading to an RMA, but I'm just a bit bothered by the symptoms. I bought the kit in my sig, including a 2GB Geil 6400C4 kit last week. I've been scratching my head as to why it won't even take a tiny overclock since I put it together. Initially, I ran Memtest and it passed fine, 1 complete run and 5 times through test 5 at 5-5-5-18 slack timings and I planned to leave it at that until I had pushed the CPU a bit, happy that the RAM was fine. I never got that far though, because even a 5MHz overclock on the FSB failed.

Tonight, just out of curiosity, I thought I'd move the RAM around to see if it made any difference (deperation move more than anything) and I discovered that it took a mild overclock apparently fine with only one stick of RAM in. So, obvously, I swapped the sticks over and it failed. Then I shoved everything back to stock and it still failed to boot. However, it passes Memtest still. Anyone know what the deal is here? Is Memtest completely useless now?

Cob · 26 Mar 2007 at 21:55

Is it at 2.1v?

mwtb · 26 Mar 2007 at 22:05

Yes, 2.1V and 4-4-4-12 timings at 800MHz, as per Geil's stock values.

Cob · 26 Mar 2007 at 22:37

Have you tried the other slots?

mwtb · 26 Mar 2007 at 22:52

Yes, although I haven't tried every possible combination. The scenario is:

Sticks A and B.

1. A in slot 1, B in slot 3 - boots and runs, but won't OC, fails intermittently.
2. B in slot 1, A in slot 3 - often fails to boot, fails within minutes of stress testing.
3. A in slot 1 - boots, runs, OCs easily.
4. B in slot 1 - as with 2

I tried slots 2 and 4 with similar results, but I didn't go through all the variations. For me the fact that the stick on its own fails at stock means I have to RMA, but my reason for posting is the oddity of Memtest happily passing it.

Cob · 26 Mar 2007 at 23:04

Yea I'd RMA it, but be sure to mention that it passes Memtest but won't boot into Windows incase they just run Memtest.

mwtb · 27 Mar 2007 at 13:14

Just as a tip for anyone who might have similar problems. I discovered that the Ubuntu Live CD was very good at detecting the memory issues (by "detecting", I mean kernel panic and/or segmentation faults). Unfortunately, I only found this out after a crash knackered my Vista install, but it's good to know.