Non-reference or "Open" cards are great if you have enough airflow.

I have a, few, fans...

http://farm7.static.flickr.com/6143/5918122770_7a8be18a2a_z.jpg

With the side panel on my case, I also get a 140mm fan blowing directly on the cards.  

Like so:
http://farm7.static.flickr.com/6132/5917556621_0c7d373e23_z.jpg

Temps at 975Mhz are between 67-72*C with GPU fans @ 50-60%