I have a 350D with a H100 in the roof currently. I had a friends build on the desk today and realised his full sized corsair case is actually smaller than my 350D wtf!? Can anybody recommend a case smaller than the 350D that will comfortably take a H100.
You can plonk a H100 in the front of a Cooler Master N200 (202 x 378 x 445 mm). Admittedly, it's not gonna rival a 350D in terms of build quality e.t.c but it's only £33. I'd highly recommend it though.
My Silverstone PS07 houses not one but two AIOs Admittedly the H100i will foul the bottom 5.25" bay and the fitting isn't standard, but I didn't actually have to mod anything, or use any special bits to fit it. It does mean losing the internal drive cage, obviously, but I got round that by ordering one of these and one of these.
All three of those are within one litre of the volume of the 350D - hardly a marked reduction in size.
