I underestimated the size of the two MSI GTX 560-TIs I wanted to put in an Antec 900 case. They're practically flush with each other, and the lower card is close to the PSU:

Am I right in thinking that's too close for proper cooling? If so, any recommendations for a larger case would be appreciated.

Am I right in thinking that's too close for proper cooling? If so, any recommendations for a larger case would be appreciated.