Watercooled 7970 crashes and blackscreens under load

[Osker_]

I bought a used 7970 with an EK gpu block (not full cover). I planned on using it in my cheap watercooled build with an i5 2320, 6gb ram, itx lga 1155 mobo, and a Corsair cx 430. I know the psu is a bit lower wattage but i dont think thats the problem. I've tested the build with a 750 watt psu and it crashes like usuall. The GPU temps nearly reach 50 C and I've tried to cool the vrm and vram with heatsinks and fans but nothing works. I've also tested other bioses for the 7970 and older drivers. Thanks in advance.

 

[Osker_]

It keeps getting worse, I just unistalled the driver the 3. time and it blackscreens without any load. I can't even install the new driver before it turns black.