Mobo only works with 2 sticks of ram

[Pax]

I've got an MSI P55-GD85 mobo and 4x2GB GSKILL Ripjaws (DDR3-1600, CL8-8-8-24, 1.6v).

I was previously just using 2 2gb sticks of some other gskill ram, and the 4 sticks mentioned above were in my wife's computer. I decided to swap ram with her, because I needed more ram for some stuff I was doing at work, but after the swap my work stuff started locking up the computer. No blue screens, no beeps, just a freeze and occasionally an automatic reboot. This happened in both Win7 and Ubuntu 10.04, both 64bit.

If I take out two sticks, everything appears normal, memtest passes and I have no crashes. If I the 3rd stick in, or all 4, memtest fails at Test #6 (Moving inversions 32bit pattern) on every single test. So far, I've tried the following thing to fix the issue or find out more info as to what was causing the problem:

• Tried at varying speeds from the 1600 the ram is rated at down to 633
• Took CPU out and checked that there were no bent pins, and that it looked like all pins had made contact with the bottom of the CPU
• Tried each stick of ram in each slot and ran memtest (all passed)
• Tried pairs of ram, all passed memtest
• Tried pairs of ram + one of the remaining two sticks and ran memtest, alternated pairs and slots (all failed)
• Tried ram voltage at 1.5, 1.6 and 1.65, all failed with 3+ sticks of ram

Is there anything I'm missing here? All 8gb worked fine in my wife's computer and passed memtest on her machine.

[keto]

1155 is pretty touchy about RAM. I'm not sure what it's called on MSI bios, but vtt/vccio is subsystem voltage, stock is 1.05 but it's very common to see 1.10-1.15v, especially with more than 2 sticks. General consensus is that 1.20 is safe for every day. One guy reported seeing a Dell stock at 1.30, I'm not sure if he was looking at the right thing or what. Anyways, I'd definitely bump that up, say .02 at a time, and see if you can stabilize it.

Make sure you set your voltage manually for whatever the sticks are rated for, and set the timings manually, not auto. Find out if it's 8-8-8-24 and 1T or 2T and set it up that way - might even try it first at 1333, memory speed makes very very little difference on Sandybridge.

[Pax]

Thanks Keto. So far, it seems like that's working. It managed to get through the mem test that was always causing it to fail. I'll let that test run a couple more times and then do full memtests. Thanks for the help.

I ended up bumping the vtt up to around 1.10

Edit:
Turns out it didn't work. Just managed to pass the tests once, after that, back to failing again. I've been tinkering with voltage, timing, etc. Nothing seems to be working. I'm wondering if it's just a bad mobo.

[clshades]

Was the 4x 2 gig set a complete set or is it two seperate 2 gig sets? I had the same problem trying to run a similar setup with ocz ram. Turns out the timings between the 1st set of ram and last set were too fast. You might find it more stable at 1333 instead of 1600 as well.

Or lower the timings slightly at 1600.

[terrybear]

Also quite possibly the board has a faulty ram socket I would also throw out there ... I would sugest tryin the ram in all slots, then pull 1 out of say slot 4, if it passes, put it back in & pull the 1 from slot 3 & ect. Eventualy you will discover if that is the problem or not & then you can start to rma the board in that instance if its the case.

Hope that helps ya some. :)