Is this RAM causing freezing/lock-ups?

[livingegg]

I am experiencing transient freezing and lock-ups on my new machine (homebuilt). The timing of the issues seem to be random - it could happen several times in a day and then not happen once for 2 days only to happen again. I have had freezes at various points of the boot process, including post (right before ram was posted), as well as during the windows loading process, while windows is running, and even in safe mode. The only place I've never had it freeze is in the bios itself.

Investigation up to this point has lead me to believe this is due to either defective ram, defective mobo, or incorrect ram settings in the bios. I want to continue to narrow things down here and need some help understanding the ram configuration in the bios.

Here is the advertised timings and voltage for the ram: 9-9-9-24-2N / 1.5V
Also, the advertised speed is: DDR3 1600 (PC3 12800)

Now in my bios settings, after load optimized defaults, the timings and voltage match perfectly. However the frequency is set to 1333 instead of 1600.

I did some subsequent research and found that the ga-p55a-ud3 when used with an i5 will not support 1600 without overclocking. So I tried enabling XMP, which boosted my ram speed to 1600, and for a while this actually seemed to fix the problems. However, this also overclocked my CPU and I don't want to do that - so I disabled XMP and I'm starting to see transient lockups again.

My understanding was that the ram should be able to scale back to 1333 without issue - so my findings here seem strange. How is it possible that enabling XMP could have fixed the issue? When setting the ram back to 1333 do I maybe need to change something with the timings/voltage as well? Or should having them set to their advertised settings always ensure stability, regardless of the frequency?

I have tried to run the newest version of memtest86 and it always reboots about 5 seconds into the testing. The multicore processor version freezes. I did get an older version to work, and scanned the ram several times, it passed with no errors.

I'll post some CPU-Z screenshots later. I'd appreciate any help with this.

-g

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Core Hardware

CPU: Intel Core i5-760 2.8GHz
Mobo: GIGABYTE GA-P55A-UD3
Mem: G.SKILL Ripjaws Series 4GB (2 x 2GB)
GPU: GIGABYTE GV-N460OC-1GI GeForce GTX 460 1GB
PSU: SeaSonic 850W ATX12

Other Hardware

HD: Samsung 500 GB SATA II
Burner: LITE-ON Black 24X DVD+R
Case: LIAN LI Lancool PC-K62
Monitor: ASUS 21.5" Widescreen 1080P

OS: Windows 7 64-bit

 

[livingegg]

I took some screenshots from CPU-Z both with and without XMP. I want to be able to run this RAM without XMP, but having XMP enabled seems to eliminate the freezing.

CPU with XMP Disabled:

CPU with XMP Enabled:

Memory with XMP Disabled:

Memory with XMP Enabled:

 

[davcon]

The last XMP enabled memory box is the correct settings.
Don't know what you've done with the cpu though in either setting.
Your bus speed should be 133Mhz in either setting unless your o'cing your cpu.
The 760 runs at 2.8Ghz so the second box looks right.
But your multipliers are wrong in both cpu boxes.
Reset your bios to default settings.
Enable XMP profile and adjust the dram voltage to the vendors spec.
I'll guess it's 1.6v minimum to 1.65v max.
Save and exit.
Have built two Gigabyte 1156's with 1600Mhz ram in both.
Two settings in bios have worked for me.