Sounds like you've got a bottom intake and front intake fans and some extra 80mm side fans (not sure where these are) in that case too that all could help cool the vga cards. The bottom and front positions have room for a 140mm fan. Is that what you've got there or do you have 120s?
What speed are these fans running at? If you can run them higher when gaming that could help a lot.
Also, is it an option to open up the area between the front fan and the vga cards by removing the lower drive bay bracket so air can flow unobstructed from the fan to hit the cards. That would probably help if after speeding up the fans you still were running too hot. http://www.hardwaresecrets.com/imageview.php?image=43614
Also, you can use a tool like precisionx or afterburner to increase the fan speed on the vga cards. That would probably be the best place to start.
fyi: ambient temperature means 'room temperature'.
edit: geez i didn't mean to steal the image, just to point at it? there's a particular image in this review that i was pointing at, i guess that counts as a crime these days (***). Hardware secrets site is annoying. It's figure 14, but you can't copy the text of that label, i guess that would be theft too.
http://www.hardwaresecrets.com/article/Zalman-Z11-Plus-Case-Review/1504/5Edited by michael-ocn - 3/31/13 at 12:33pm