I just got my new 5770 today to compliment my other one, both same brand and model. However, my windows 7 machine with a GA-eP45-UD3P mobo does not detect the second card. Both cards work if placed in the #1 slot, but don't work at the same time. Both cards also get power (fans run) when both seated in their PCIe slots.
Yes I was. I actually ended up figuring it out. There was a screw close to the card that was causing the mobo to be bent a bit, also causing the very back of the card to be about a 64th of an inch from being seated properly. Removed the screw and re-seated the card, it worked.
I read an article here on Tom's about that, I can't locate it though. Anyway it pointed me to an article an Anandtech about how to spread thermal paste. It suggested you use a two-line method. Use two rows about a third of the CPU apart. And use a line that isn't too thick, less than a grain of rice. Looking at the picture it covered about 97% of the CPU, sparing only the corners.