Weird Memory Issue

MickeyD

Built a new PC recently and thought everything was working fine. Then I started to get CRC errors in installers even though they would work fine later, and getting occasional PFN_LIST_CORRUPT blue screens so I figured I had a RAM issue.

I ran a memtest and sure enough it failed on test #3. I then tested each individual module (i have 4) in the same slot on the mobo and they all passed a single pass memtest. I then tested them in pairs of two (in the same two slots) and the second set failed on test 3 again. However they passed when I tested each one of that set individually.

I then put all four back in and it failed memtest again. I reseated them in different slots and after this the memtest passed for 6 hours. However the next day the same crap started happening and when I ran memtest it failed again.

I have increased the QPI and DRAM voltages but doesn't seem to make a difference. Also running at stock speeds and timings. Motherboard is a gigabyte ga-p55a-ud6 with the latest BIOS and I'm using G.skill cas7 ddr3 ram, 4x 2gb modules.

I know there's an issue with my RAM or motherboard but the problem is I'm just not sure which. Would there be any way I can test this to make sure I know what to RMA? The ram came in 2 packs of 2 so preferably I'd be able to figure out which RAM module(s) is causing the problem so I can continue to use the PC (if indeed my mobo is ok).

What I'm thinking of doing is taking two sticks out, running with two for a day or two, then swapping into the other two slots on my mobo and letting it run for a day or two. If I'm blue screen free then I can assume it's a problem with the other two sticks. If I get a blue screen when i swap into the other two mobo slots, then it's the mobo (:() I'm not sure if this is a good way to go about it though!

VenomIreland

What Voltage is the RAM rated for? I am guessing it is probably 1.5 or 1.65, try the one it says on the box/RAM modules.

MickeyD

It's rated @ 1.6v. I bumped it up to 1.64v for good measure but still failed.

VenomIreland

Hmm, very strange then, I honestly don't know what more to do, you'll have to wait for other's help.

MickeyD

np, thanks anyway!

Curry Addict

one of your sticks of ram is highly intermittant. if u leave it running mem test overnight, just one stick at at time, u identify which one soon enuf with little hassle. in the meantime contact your supplier and arrange return.

EL_Loco

maybe try each ram1-4 in each slot1-4 individually. this may help identify a dodgy mobo slot.

test1, Ram1,slot1
test2, Ram2,slot2
test3, Ram3,slot3
test4, Ram4,slot4

if you get one slot erroring then take that Ram and put it in another slot and retest. If that passes it looks like the slot.
to confirm take a ram that passed in another slot and put it in the suspected slot.

bit drawn out, and you've already hinted at something similar but anyways, typing practice eh!?

edit: when it does fail boot into bios and check temperatures, maybe something quietly going on on that front.

MickeyD

Temps are all fine usually, around the 30 degree mark but its pretty warm in my room these days, but ill keep an eye out.

The problem with testing the slots is that the mobo will only POST in certain ram configurations. If I put a single module in slot 2 for example, it won't boot as it expects it in either slot 1 or slot 4 (mobo has 2 banks of 3 slots) when there's a single ram module installed. This means I can only test slots 2 and 5 when slots 1 and 4 are already filled which is pretty damn annoying.

I ran the memtest there again and took note of what region of memory the test failed in (e.g. its limited to the 0-2048MB memory address region). I then swapped each set of modules around. Memtest then passed. I'm going to wait until it fails again and then see if its the same memory region as before. If it's different then that would suggest it's the ram and not the mobo. Unfortunately I don't know how the slot numbers map to memory addresses and if it actually is consistant between boots.

Other than that I will run the RAM in memtest overnight one by one. If they all pass I guess its a mobo RMA

MickeyD

Memtest fine last night for 6 hours. Booted up today and got a BSOD after 5 mins, ran memtest again and this time the error was in a different region. Sounds like dodgy ram to me (assuming the memory ranges are consistent between boots).

BigEejit

I had the exact same issue, it did my head in as I could not pin it down to either the mobo or ram.

I finally just put it down to incompatibility because I took the ram and swapped it into another PC and swapped that machines ram into this box and both ran fine for ages.

I also noticed that I wrecked my Windows 7 installation with all the bsod's and it was still occasionally bsoding. A fresh install and it has not bsod'd again since.

MickeyD

Yeh, could be something like that alright. Unfortunately I don't have any other RAM or mobo to test. The ram is listed on the mobo's supported memory page but its the CAS9 version not CAS7, although I was still getting issues running at CAS9 timings.