I've also received my cases on Friday (both, a silver and a black - will be doing 2 builds). As i started taking my "desk-build" apart on the weekend and tried to do some "dry-fits" i realized that both of my alpha-cool rads don't fit (they're too wide). So either i put the fans on the "outside" or i go and get some other rads (cause with fans on the outside i would blow the hot air inside the case and also wouldn't have much space for the fittings. I think i could also take off 1mm on each corner of the rad (cause it's really not much). On top it just bends the push-pin holders a bit to the side (havent tried closing the case with that).
@dondan: which radiators did you use/test with?
mine are the AlphaCoolNexXxoS HPE-30 and NexXxoS HPE-45
Also: Now that its inside the case i could see that - as with the AMD board previously, also on the Intel board (Asus Z790-I) the GPU Backplate collides with the Chipset/VRM Cooler Block. It fits, but the GPU is not perfectly lined up straight. Positive fact: From the height perspective the 30mm radiator with the full-size 25mm fans on top fits perfectly above the GPU on the top of the case (even some space to get some air :-)).