Agree with stickmans88 in general.
I have a E6400 @ 3.2 w/ 4870.
A couple of notes -
(1) sides and top. will need to try diferent configs
(2) side - If located at top back, I use exshaust and on lower center/front I use intack. Need to try. On my system the 4870 blocks the System temp (I believe it's the north bridge) causing an increase of temp to 39 -> 41 C
(3) top fan, may interfer with CPU air flow ie I have rear 120 by 39 mm) as an exshaust, CPU HSF blows air toward this fan. A top fan may subtract from the air flow across the CPU heatpipes/fines. ( there was a post on this.
Have the colormaster 690 - not totally happy with it. My sligthly modified old case w/PSU at top and no top fan did a better job at cooling.