SOLVED Prime95 Rounding errors on stock settings

[louis_m12]

Okay, so I've been experiencing blue screens and haven't been able to pinpoint the cause until I discovered that my CPU runs into errors when I run a Small FFTs test in Prime95.
I've run Prime95 in Windows 7 and Windows XP to see if it was just the OS causing a problem. Is there any way I can fix this or will I have to send the CPU off to AMD for a replacement?

System Specs:
OS: Windows 7 64bit/XP 32bit
AMD Athlon X3 455
8Gb DDR3 Ram
AMD Radeon 6670
Biostar A780L3L Motherboard

 

[RollingThunder]

Louis,

Unless you have a heat problem it's more likely one of your RAM sticks is the problem if you're testing at stock speeds. Run a RAM memory test such as Memtest86.

 

[louis_m12]

I thought it would be a ram problem, but I left Memtest on for 8 hours and it didn't find any errors... Could it be that the motherboard is just messing things up? Biostar doesn't seem to be the best make

 

[RollingThunder]

I thought it would be a ram problem, but I left Memtest on for 8 hours and it didn't find any errors... Could it be that the motherboard is just messing things up? Biostar doesn't seem to be the best make

What memory testy did you use? Memtest V2.11 from a boot disk seems to be more thorough (for me). Motherboard diagnosis is much more difficult.

 

[louis_m12]

I used Memtest v4.20 usb installer version, is there a usb installer for V2.11? That's the easiest option for me

 

[trents]

Louis,

Unless you have a heat problem it's more likely one of your RAM sticks is the problem if you're testing at stock speeds. Run a RAM memory test such as Memtest86.

Possibly, but the small FFT Prime95 test doesn't engage the ram much. The evidence suggests a CPU issue to me. Doesn't happen very often but it does happen. It could alos be a heat-related issue. Louis, have you done any temp monitoring while you are running Prime? Please download and install HWMonitor. Have it open as you begin another Prime95 stress test. Post back with a pic of the HWMonitor interface so we can see what your core and CPU socket temps are like.

What CPU cooler are you using? The stock cooler that came boxed with the CPU or an aftermarket unit? If the latter, make and model please. What about your case ventilation. How many intake and how many exhaust fans do you have going? Is your ambient temperature very warm?


Those CPU-z pics will give us a lot of info about your system settings and help us spot potential wrong values.

 

[louis_m12]

I looked into the bios settings and checked the CPU settings. There's not much there but there's an option for 'Custom P-states' I enabled that and found a bunch of options for voltages and clock speeds and all that, but none of them are able to go any higher than the stock settings other than the 'NB FID' which is able to be raised to 2000mhz.

As for my CPU cooler, I'm using the stock AMD heatsink and my room temperature is fairly cool. On my case I have a large intake fan in the front and in the back I have two exhaust fans.

Here's HW Monitor before Prime. The motherboard temp is certainly strange...
HW Monitor Before

 

[trents]

Except for that 121c motherboard temp (which is probably a bogus reading) I don't see anything else in HWMonitor that looks out of whack.

How about posting those three CPU-z pics?

 

[louis_m12]

Which three do you want? Here's CPU, Mainboard and Memory
CPU
Mainboard
Memory

 

[trents]

Sorry, I should have been more specific. CPU, Memory and SPD. The SPD one is important because it displays the RAM manufacturer's recommendations for voltages and timings at various frequencies. Please attach them directly to your post as you did with the pic of Prime95 in your earlier post.

 

[louis_m12]

No worries, here's the SPD tab:
SPD Slot 1
Slot 2

 

[Johan45]

Running dual channel with two different memories might cause a problem. Pull one stick out and see if the problem still persists.

 

[trents]

Louis, please attach the pics directly with your posts instead of linked. It is easier for those helping you that way.

One potential problem I see from your CPU-z pics is that you are mixing brands and speeds of ram. That is a no no. You are running Micron in one slot and Crucial in the other.

As an experiment, remove one of the ram modules and retest with Prime95.

 

[Johan45]

Ha ha you been NIJA'D Trents

 

[louis_m12]

Okay, I'm only using the Crucial stick now and I'm running Prime so we'll see how this turns out.
Even though they're different makes of ram, I thought they were the same speed? both 1333mhz sticks?

 

[trents]

But their timings are different at the same frequencies.

 

[louis_m12]

Oh right, my bad... Also, my CPU has passed the 20k test on Prime95 with no errors so far, looks like it may have been a ram conflict. I'll remember this next time I'm buying ram. Is it a good idea to leave this test running over night to be thorough?

 

[trents]

Oh right, my bad... Also, my CPU has passed the 20k test on Prime95 with no errors so far, looks like it may have been a ram conflict. I'll remember this next time I'm buying ram. Is it a good idea to leave this test running over night to be thorough?

I think two hours is plenty.

Also, you might be able to run the ram in single channel mode and use all the sticks. But it seems it won't allow dual channel mode which was how you had it configured. When you run single channel mode you give up some performance, however. When you buy ram, buy it in a factory certified dual channel kit. That is to say, buy both sticks together in a kit to ensure they are a matched pair and come from the same production batch.

 

[Johan45]

When you buy ram, buy it in a factory certified dual channel kit. That is to say, buy both sticks together in a kit to ensure they are a matched pair and come from the same production batch.

 

[louis_m12]

Alright, thanks for the help guys. If I need the extra 4gb I'll try running it in single channel mode, but for the moment 4gb will do.