I have 2 6870s in crossfire and my main card is always idling at 60c. Admittedly it doesn't have as much ventilation as the second card, but I would think it'd be a little cooler. At full load I've seen it hit 88c. My memory on the main card is at 1050 no matter what, and I've tried swapping around the cards in case it was a bad sensor or something. It's not. I've deduced that the 1050 mhz memory is because I'm running multimonitors... does anyone else have a similar setup? Should I worry about temps?
The specs for your case say it doesn't come with a intake(front) fan.Do you have a fan in the front?
If your XFX 6870's are the reference design then the high temps are normal.Reference cards have horrible heatsinks.I suggest adding a fan in the front if you don't have one already and add another fan or 2 to the top for exhaust.Better airflow should bring the temp down a little.
EDIT: I just looked again at the specs for your case and the pre-installed fans aren't that great.They run at 42cfm which doesn't move a lot of air at all..I suggest you populate all of your fan slots with new fans.That should dramaticly reduce the temps for both 6870's.
I own a 6870 and I looked everywhere for a aftermarket heatsink but they are scarce.The only "good" ones I found were from Arctic Cooling.They are really good heatsinks but the bad thing is that they are expensive and i'm told they take up three slots.
I jusy looked at the case it looks like a nicer version of the gama. Change the side fan to intake it will blow right on the cards. Make sure the back fan is venting out and if you can face the heat sink fan to blow towards it, and make the front fan pull in as well, my case is almost the same and my temps are good, try it out its a free 20-30 minute fix. It will likely clear that up nicely Im guessing 8 C chane at least.