i have 2 gtx460s i put them both in the x16 slots but my 1st card had bad temps because it was right near the second card and wasnt getting much air so i moved my 2nd card in the x8 slot to give it more room and temps have gone down about 10c which is good will they both work in sli and will they both peform as x8
Are you running more than one monitor? Unless you are running multiple displays the difference between 16 X 16 and 8 X 8 is non-existant. A single monitor is saturated by 16 lanes of PCI and the extra bandwidth is redundant.
+1 to mousemonkey. You need to list (at minimum) your mobo, and any other peripherals which would influence (interfere with) your slot selection.