820-3332-a ...


New member
Hi friends,

i am repairing this motherboard and i have some strange problem.

The mac after start Unigine Heaven with GPU Nvidia 650M freezes, and logout from the OS.... really only logout from the OS! I must enter the password to the OS and i can continue. The computer does NOT restart or shut down with message GPU panic as is customary. Only freezes and logout. When i start Unigine Heaven with Intel GPU, everything is ok... so, the problem is with only NVIDIA GPU.

I try replaced GPU for a new one and reballing GPU-RAM, replace U8900, but the problem is the same.

Can you anybody help me? Some idea?

Thank you very much.


I have had some issues with Unigine and Nvidia GPUs. I'm not sure what is going on but it may be a software issue. Try some other GFX stressing programs and see if those also make it crash.
anyone having this exact same issue, i.e.: looging out when dGPU is active and under load:
it's not a software issue, but a sign of a bad U8900.
Had this happen multiple times this week and after getting them all equipped with better ISLchips, the problem went away.

hope this helps someone


Super Moderator
Staff member
We use Unigine Valley to stress test machines. No issues software wise crashing on known good hardware out of thousands of machines.

Was U8900 replaced before or after replacing the GPU? This could be a internal trace issue between GPU / VRAM / U8900 or bad / cracked ball under VRAM.
I assume you?re asking the guy who opened the topic here? this is an old topic but I thought I?d just add my experience to it for anyone?s future reference.
In my case it were faulty u8900s