This thread got me thinking and I'm now ordering a new tube of AS5 and am gonna do both of my 5770s as well as my 1090t. My 1090t with corsair h50 Idles at 40 degrees Celsius in a 70-72 degree Fahrenheit room and my 5770s idle in the mid to high 50 degree Celsius range.
I think I need to do the northbridge screw mod to my crosshair iv formula also. It idles near 65-70 degrees Celsius.
My room is also 70f and my 1090t runs at 38c load under an H50 push/pull with the stock fan as push and a cheap fan I got from Fry's for pull. If you're at 40c idle then you really have some issues. My paste of choice is MX-3. I used to use AS5 but I switched to MX-3 because several tests have shown that it results in lower temperatures than AS5, no cure time (AS5 takes a few days to reach maximum effectiveness) and is electrically nonconductive.