here i have a video showing the results and temps you can achieve with the nzxt g10 on the amd r9 290x
as you can see even in crossfire and running 5760x1080 at ultra it doesn't go above 55 degrees
note: im sure you will all go balls to the wall with hate but the fact is the r9 290 and 390 and the 290x and 390x are the same card
infact the 290x and 390x both have 8gb the 290 was 4gb and the 390 is 8gb however they still give the same performance