Regarding the Hyper 212X I purchased recently to fit a Gigabyte Z170XP-SLI motherboard (i7 6600K) I am so in tune with your probs John re the threads on the spacers and connection to the backplate through the motherboard. Given the clearance at the back of the motherboard re the cutout I have on my case ! The thread on the so called 'D' spacers went through the motherboard and touched the backplate with next to nothing of the thread coming through! Given an extra 2mm or so would have made the complete installation a breeze BUT no! Which makes me bewildered that these so called designers of this gear can't seem to be on the same page when it comes to actually testing the gear on a real motherboard configuration - if they had the problem would have been instantly recognized! OR are the motherboards they're testing them on super THIN!! Luckily I DID get the 'G' spacers to fit and though loathe to risk the CPU as Cooler master show the 1151 installation using the D standoffs as correct fitting - I am assuming that so long as the thermal paste / conductivity is established I should NOT have any further problems. My advice to Cooler master is SORT your act out!! An extra 2mm on the thread please!