Ok, I recently broke a pin on a molex to 6 pin PCI power connection, I had no spares around so ordered a replacement immediately. Once it arrived I noticed that the plastic housing on the connection was ever so slightly different than before in that it had a square pin where as on my old connection it was 'rounded' (I hope you know what i'm talking about so far). So I removed all the pins and put them into the old plastic housing and made sure each pin was in the correct slot. edit: i.e the 6 pin connection was unable to fit in the GPU because the plastic housing didn't match up. Whilst I was waiting for the replacement I had a BFG 8600GT OC running in the 275s place, so I got the 275 back out of the box where it had been stored for a day or two, popped it back in, put the PCI connections in (my PSU only has the one) and of course the one I had just fixed. When I tried to startup, nothing, the PSU made a very faint clicking noise. I put the 8600 back in and started up with no problems ( I tried this several times to make sure I wasn't just being an idiot as per norm ) My PSU is a 600W and until today has been coping fine, and has no problem with any other GPUs. I have recently had a GTX260 fail however it never prevented me actually starting my machine. Have I made a silly error, or am I just burning my money with dodgy GPUs?