Got a strange problem here. When i put my Zotac GTX 480 in PCIe_x16_1 I get full x16 2.0 speed but as soon as I stress the gpu the system will freeze.
When i moved it to PCIe_x16_2 i got x8 2.0 speed, and the card works 100% fine when I put some stress on it...

Everything at stock, any suggestions?