I use the Xigmatech Dark Knight in my Antec900 on an i7920 and it fits just fine. It looks like it's not going to ... but it fits without hitting the side panel. Plus, since positioning of the very big 140mm exhaust fan on the top of the case coupled with the direction of the HS/fan when installed it makes for a decent cooling solution. I have my rigged overclocked to 3.82ghz with turbo on and HT enabled and my idle temps are 30C and about 50C under load after running prime.