The Stock Cooler for the Gigabyte 7970 isn't the greatest.   When I had these cards a year I ago, I know they 80^C under good conditions.  The current 7970 that I have running, was going to 100^C and then throttling down.  I had to get an after-market heatsink/cooler.  I spent $50 on the Gelid and so far, it's money well spent. 

While on the topic of just after-market heatsinks/coolers.... I bought the Arctic Accelero for my 6990's.  WOW.... while I got a deal off ebay for two of them... I would have paid full retail!  The temps are low and MUCH Quieter!  I live in  an apartment, so for the sake of my Sanity... Quiet is good!  I do have one rig that is water cooled.  I think eventually i'll have to be doing this for everything... especially once we're in summer.  But that's a long term project.