Generic GPU (or CPU) blocks may be put on mainly something with a little less than exquisite affixing (though GPU blocks are inclined to have the holes on the aspect, so are preferable).Removed the M4000 with the x16 slot (my P400 is used for the OS on the x8) and plugged from the x1 riser, related "USB" cable for the riser as well as GPU.one. Amin