Prime95 fail after OCing

IKMS

IKMS

IKMS

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Ok, so I have a Phenom II x4 810 (yes it's a bad CPU but I already know that). I OCed it to 3GHz using the BIOS and ran the AMD OverDrive Stability Test for an hour.

It was successful in AOD so I ran the Prime95 Blend test.

After 5 minutes the Worker 2 and Worker 4 failed at the same time, even though my CPU was at 42c and Mobo at 38c (according to PC Probe).

Is there any reason for this? I have no screenshots but I can get them if needed. Worker 1 and Worker 3 continued after the other ones failed until I switched Prime95 off.

Thanks in advance.
 
not enough vcore usually.

AOD doesnt stress the cpu like prime does, you need to look at some overclocking guides to learn how to set the vcore for your chip etc.
 
lemzip said:
not enough vcore usually.

AOD doesnt stress the cpu like prime does, you need to look at some overclocking guides to learn how to set the vcore for your chip etc.
Click to expand...

I read my Motherboard manual and there seems no apparent Vcore settings.

There is an OverVoltage setting, but I left that alone.

My motherboard is the M4A785D-M PRO.
 
Yep, it's probably like lemzip said, not enough vCore.

Try raising it a little bit and then retest, also, you might want to double check your memory to, make sure it's running within its spec and you have the right amount of vDIMM applied.

Prime failing on threads is a sign of instability, AMD Overdrive obviously isn't stressing the CPU hard enough for it to fall over.

The overvoltage setting will probably be for vCore, however, I can't confirm this as I don't know your mobo's BIOS.
 
might be listed under cpu overvoltage or similar.

Find out your cpu's voltage rating (on amd's site or similar) and set it to that and work from there.
 
add: your board is similar to mine, in the bios you should have a menu called jumper free settings, its in that menu under cpu voltage.
 
I wrote it down in advance of overclocking, it is 1.216.

Does that sound like a reasonable vCore setting?
 
I'm not up to scratch with current AMD processors, but I personally think that is pretty low tbh mate, this is more than likely why Prime is falling over.

When I had my 6000+ X2 I used to need 1.55v for 3.5GHz, however I can't really compare my old chip to yours, I imagine the 45nm AMD chips need quite a bit less voltage.
 
Gonna set it to that in about 5 minutes, I will then run Prime95 again and re-post here with results.

I hate my 810 >=[

Edit: If anyone wants to buy it off me for 100 pounds then I will oblige, I would much prefer a 955 or 965... (A swap of my 810 for your 955 is allowed aswell :D )
 
you wont get £10 for it let alone £100 lol :D

Anyway,voltage wise AMD in general will take more then intel most people are fairly happy to run 1.55 vcore on the 45nm AMD chips which i did np. For a 3Ghz i would just set 1.3Vcore in the bios run prime if does you target time you can lower the vcore or even go for 3.2ghz depending on temps. Not the best way to o/c bu will serve its purpose here
 
Ok, thanks BBAl I will try that after this.

Just a little update image. It failed again :(

Untitled-2.png
 
Ok...

Ramped up the vCore to 1.3v and turned up to 3.2GHz.

PC had a grumpy fit and wouldn't load windows.

Upped to 1.3375v and still no windows.

Reduced FSB from 246 to 236 and kept vCore the same and I booted.

Currently running Prime95 again.
 
When your trying to get a particular frequency stable, its best to not play around and start upping the FSB. Get your current freq stable then push for more.
 
Have you made sure you're not overclocking your RAM at the same time mate?

You need to be adjusting the RAM ratios when you raise the FSB so that your RAM stays within its rated spec, also adjust timings manually to incase the BIOS is setting them to tight when you use the auto settings.
 
Right, I am going to change HT multiplier to 9x.

I looked in the BIOS and when I chose to change RAM Timings it comes up with a list of 26 options all set on Auto.

I read a guide on how RAM Timings work, so hopefully I can get this RAM to like me.
 
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