Probably an ugly idea, but in a closed case, might be a worthwhile experiment.

What if you build a direct vent around the mouth of that monster, directly to the rear fan port on your case?

I am betting this is a mod project that would pull your mobo temp down at least a couple degrees centigrade.

This type of design really demands a case that rejects heat well at the rear. If you have that natively with a big fan, that's one thing, but with a fan and a duct, not practical mind you for a pretty case install, but for a closed case where temps are the only concern you might gain some performance guiding that side rejected heat through a duct right out the rear exhaust.