You surely got a large exhaust on top of your case haha.

I not sure whether can I mount it horizontally or not, my case doesn't have that large exhause on top. Can only depend on the PSU exhaust.

Corsair hx620w ran out of stock everywhere, If I get PC&C then no exhaust on top already.

How you gonna mount HR-05 SLI anyway? After you mount please post a photo