The DIMMs of DOOM

October 16, 2008 2:33 PM

Windows XP PC crashes and burns when four identical sticks of RAM are installed but Memtest86 shows no errors.

I'm beefing up a PC that has an Intel motherboard (D865GBF) with four dual channel DIMM slots. I have four identical 512MB DIMMs that are certified for this board.

Here's the problem. THE PC works just fine with two sticks of memory in DIMM 0 in both channels A and B, but adding two more sticks to DIMM 1 causes the PC to fail in various ways. The PC may or may not load Windows XP. Various applications will crash randomly. XP will always eventually blue screen with different STOP codes. The STOP codes aren't pointing me to a solution.

The BIOS recognizes all four sticks when present. The Antec 380-watt power supply is new. I can fully stress the CPU and video card simultaneously with only DIMM 0 loaded, however the PC eventually crashes and burns while idling when all four slots are loaded.

All of the sticks work successfully in DIMM 0 channels. Adding any two sticks to DIMM 1 channels causes the grief. I've eyeballed the DIMM 1 slots and they don't appear to be damaged, but I'm guessing that one of them is toast.

Here's the mysterious part. I've loaded up all four slots and run Memtest86 for hours without error.

I'm stumped. I feel like I'm missing something obvious here. Any ideas?

posted by shinybeast to computers & internet (7 comments total)

I had a similar problem a couple of years ago, and completely fixed it by replacing the motherboard. You could always do that to see what happens, and if the error persists just return it.
posted by crapmatic at 2:51 PM on October 16, 2008

I'd second the logicboard. But it could still be the rAm. Memory tests are most useful when they indicate a fault; often a bad dimm won't test bad and the only proof it's bad is you don't crash when it's swapped out. You could order a fifth identical dimm and rotate all the others out in turn to isolate the culprit. Whether that's less annoying than swapping out the logic board depends on the result of that test.
posted by maniabug at 3:06 PM on October 16, 2008

Are the DIMMs double-sided? Some older motherboards only support single-sided DIMMs on the second channel. Try throwing a pair of matched older RAM into DIMM1 and the new stuff in DIMM0 and see if it's all recognized by the OS and boots OK.
posted by Civil_Disobedient at 3:57 PM on October 16, 2008

The two sets of RAM might not be compatible with each other. Have you tried only filling 3 slots, or 1 of each in slot 0?
posted by wongcorgi at 4:26 PM on October 16, 2008

I had a similar problem with a Lenovo PC. Turns out that it was the Motherboard logic. Initially, I had to live with it for a year,just using a single 2GB stick. Then Lenovo updated the firmware and it fixed the problem. Have you tried using a larger DIMM?
posted by Susurration at 5:32 PM on October 16, 2008

A while ago I had a similar problem. 4 sticks of ram, none of which tested bad, but they my comp wouldn't boot. Eventually I swapped them around. I went through all 24 permutations of orders they could be set in. Only the 24th worked. Never figured out why. Try putting the RAM in a different order.

Also, check out your motherboard's specs. My current one lists which RAM it will and won't work with. I haven't tested its nonworking list, but I'm still curious if any of yours aren't listed as compatible.
posted by valadil at 9:01 PM on October 16, 2008

Have you updated the BIOS? I've had issues with a few computers where the BIOS gets confused and sets memory timings wrong. They ran Memtest just fine too. See if you can find the details on what the memory timings are set at in your BIOS. Then update the BIOS and see how well things work. If it keeps crashing, go back into the BIOS and see about changing the timings by hand. I think if you google around you can probably find info on an overclockers site or something on how to tweak memory until its stable.
posted by Good Brain at 11:54 PM on October 16, 2008