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Unlocked x4 B55 + nvidia vga = incompatible?

Last response: in CPUs
March 18, 2011 7:28:48 PM

Hi I'm having a lot of trouble figuring out what may be causing the strange problem I'm having with this combination. First, here are some relevant specs

A-DATA DDR3 2x2gb 1600 ram
Phenom II x4 B55 (unlocked 555)
Gigabyte 560 ti SOC (950mhz core)
Asrock M30770~ mobo
Apevia 700W PSU (it's crap but comparable to at least a high end 550W)

The problem - When my BIOS recognizes my processor as a 'Phenom II X4 B55' rather than the standard 'Phenom II X2 555', my Nvidia drivers (255.68 and 266.66, two SEPERATE, WORKING, cards - not in SLI - one or the other was installed) fail during anything that is even slightly graphic intensive - basically anything that will put even a 1% load on the GPU.

Here is some troubleshooting I've done:

B55 with all 4 cores unlocked passed a 12 hour prime95. - Nvidia drivers fail

B55 with cores 3 and 4 disabled - Nvidia drivers fail.

Stock card (recognized as x2 555) the nvidia drivers work.

Can anyone tell me why on earth the Nvidia drivers would fail even if the 'unlocked' cores are disabled? They showed to be stable after a 12 hour 95prime so technically they should not be problematic to begin with - but for Nvidia drivers to fail even with the two new cores disabled baffles me. This indicates that my bios simply recognizing the CPU with a different name is causing the video card drivers to fail.

Anyone know why this could be? Any help is GREATLY appreciated, this is one of those odd problems that drives me insane because there is no readily available explanation.

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March 19, 2011 12:03:17 AM

There is apparently a communication error between the unlocked CPU and the rest of the system (GPU). Could be the reason the CPU was sold as X2 555! Just for the hell of it have you tried another card?
a b à CPUs
March 19, 2011 12:18:08 AM

Incidently I do have an unlocked Phenom II X4 B55.

One of my cores was crapped, so when I ran anything remotely intense it'd die.

Try updating to your latest BIOS and try disabling core #2 or core #3 one at a time and bump up the voltage.
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March 19, 2011 3:29:35 AM

disabled cores 3 and 4 (same time) and the drivers still failed

I tried two different video cards, an EVGA 460 prior to the SOC

rolli59 - i definitely see where you're coming from on the 'reason it was sold as x2 555'. I'm done messing with this thing now, just wanted to see if anyone had a clue how it could pass the prime95 twelve hour test and cause video card failure


i'll never know, done worrying about it
a b à CPUs
March 19, 2011 6:40:15 AM

What about your power supply?
March 19, 2011 11:43:39 AM

apevia 700W

it's definitely not the power supply, i can play AvP benchmark on max settings no problem with x2 555, but if i use only 2 cores on x4 b55 the card drivers fail.

Best solution

a b à CPUs
March 19, 2011 11:51:40 AM

Oh well, I guess you got what you paid for.

Enjoy the CPU regardless, it's pretty damn good.
March 19, 2011 6:03:29 PM

Best answer selected by billage.
March 19, 2011 6:03:52 PM


got it stable at 3.8 right now :)