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GA-P55M-UD2: 64-bit Win 7 stable with 2GB RAM, crashes with 4GB

Last response: in Motherboards
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Hello. I am posting this in Motherboards and Memory because I suspect that is where my problem lies. However, as you will soon see, this is a VERY strange problem and if you feel that it belongs elsewhere, please let me know.

My newly built system boots and runs just fine (e.g. I can play games like Dragon Age for hours) with 1 2GB RAM module installed, but when I install the second 2GB module, my system locks up completely approximately 30s to 2m after I get to the Windows login screen, whether or not I log in. The time it takes for this to happen is variable within a short window of time, but it ALWAYS happens. There is no blue screen or error message in the event log other than the Kernel Power error from the required hard reset, the whole system just locks up completely. Even Windows setup locks up this way after approximately a minute. However, I am able to boot into Safe Mode and run that way for an indefinite amount of time without any lock-ups.

My system:
Antec EarthWatts 650W
Gigabyte P55M-UD2 Rev 1.0
4GB Corsair DDR3-1333 RAM
Intel Core i5 750
Radeon 4850
64-bit Windows 7 Ultimate

Everything is being run at stock speeds and timings. I have not done any tweaking.

Troubleshooting Steps Taken So Far:
Verified that the memory modules and their speeds and timings show-up correctly in the BIOS status screens.

Ran several passes of MemTest86+ with 4GB RAM installed. All tests passed.

Tried multiple sets of 2 x 2GB RAM modules. All show same behavior: stable with 2GB, lock-up with 4GB.

Tried memory in both dual-channel (slots 1 and 3 on my mobo) and single channel (slots 1 and 2) configurations.

Upgraded my BIOS with QFlash (NOT @BIOS) to both the F5 and F7c versions. Same behavior.

Tried disabling most of the on-board mobo features in the BIOS (like Audio, Firewire, USB, etc) to narrow down the problem, but it had no effect.

Tested all of my connections on the motherboard.


One thing that I have NOT been able to do is get my hands on a 4GB RAM module, so I don't know if this is a problem with the AMOUNT of memory or the number of modules. I suspect that it's the latter, but I can't be sure of that.

At first, I thought this was a driver issue since I am stable in Safe Mode but not in setup or normal mode, and that may be the case. However, it cannot be related to a driver I installed since Windows setup from a DVD-ROM encounters the same issue. Also, I have NEVER heard of drivers behaving differently based on how much RAM or how many RAM modules are installed. The fact that it locks up consistently after Windows boots without giving any sort of error messages in the Event Logs or without a BSOD makes me skeptical of some sort of driver issue.

What could possibly be causing instability with 4GB of RAM that would then allow stable operation with 2GB? I am totally stumped. Anyone have any suggestions?

More about : p55m ud2 bit win stable 2gb ram crashes 4gb

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bilbat said:
First thing: you can check the setups (2 vs 4) against each other by downloading MemTest86+:
http://www.memtest.org/download/4.00/memtest86+-4.00.is...
The iso burns to a bootable memory tester; run it one full pass (at least) with each DIMM installed by itself, then run it again with both installed; if it fails one of them, you've got a dodgy stick; if both pass individually, and the 4G fails, it's your memory setup...


Hi bilbat. I already ran several passes (approx. 10) of memtest86+ against the 4GB configuration of memory as mentioned in the OP. I'll try running it against each DIMM individually, but since I have already tried 3 different sets of DIMMs, I doubt that this is a memory hardware problem.

Cheers.
Motherboard Expert

I have the same board. Which slots did you test the RAM in? And let's talk about this in relation to the CPU because Gigabyte numbered the memory slots in a confusing order. The slot closest to the CPU is 2, then 1, then 4, and finally furthest from the CPU is 3. So the order is 2, 1, 4, 3. Not exactly clear is it?

For two sticks of memory, you should be installed in the second and fourth slot from the CPU. So the closest slot to the CPU should be empty, and the third slot from the CPU should be empty. This should be the same as populating the white slots and leaving the blue ones empty.

For one stick of RAM, the second slot from the CPU or the fourth slot from the CPU should be populated. Again, this should be either white slot.

If that is what you have done, it would help to have more specifics. Please provide a link to your RAM. Also, what are the settings in BIOS that you changed and what did you set them to?
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Motherboard Expert

It looks like to fix the problem you moved the memory "Performance Enhance" from Turbo down to Standard and changed the QPI/Vtt Voltage from 1.1 to 1.25 V. It's possible one of the changes by itself would have solved the problem. If you're up for some more testing, change the Vtt back to 1.1 and see if Performance Enhance by itself solves the problem. If not, change Vtt back to 1.25 V and set Performance Enhance to Turbo and see if that solves the problem.

I am a little curious about why a QPI / Vtt of 1.25 V was chosen. Intel rates the "absolute max" for this setting at 1.21 V. I see people go higher but usually they are overclocking. You could also try lowering this V and see if the system remains stable. Or maybe it doesn't really matter.

bilbat, what do you know about the QPI / Vtt setting? Any insight you can share?

Hi,
I've had a similar problem with the same board in the past - Apologies if this does not help, but you might need to increase the voltage in the BIOS to your RAM... it's set at standard as 1.5V, but i also have 2X2gb of DDR3 1333mhz Corsair RAM, and it actually requires a voltage of 1.65V to run without experiencing the intermittent freezes. I upped the voltage to 1.64V (due to it only letting me increase it in blocks of 0.02V) and the system ran smoothly after that.

ekoostik said:
It looks like to fix the problem you moved the memory "Performance Enhance" from Turbo down to Standard and changed the QPI/Vtt Voltage from 1.1 to 1.25 V. It's possible one of the changes by itself would have solved the problem. If you're up for some more testing, change the Vtt back to 1.1 and see if Performance Enhance by itself solves the problem. If not, change Vtt back to 1.25 V and set Performance Enhance to Turbo and see if that solves the problem.

I am a little curious about why a QPI / Vtt of 1.25 V was chosen. Intel rates the "absolute max" for this setting at 1.21 V. I see people go higher but usually they are overclocking. You could also try lowering this V and see if the system remains stable. Or maybe it doesn't really matter.

bilbat, what do you know about the QPI / Vtt setting? Any insight you can share?


Thanks for the insights. I scaled back the QPI/Vtt voltage to 1.19V and it's still stable. I am going to try scaling back to the base 1.1V setting and see if that works. I suspect the problem has more to do with the Performance Enhance setting than anything else.
Motherboard Expert

sqrmap said:
I suspect the problem has more to do with the Performance Enhance setting than anything else.

That's where I'd put my money, too. Which is why my first test suggestion was returning QPI/Vtt and testing with PE = Standard. Please keep me posted, I'm curious to hear what you find.
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