Well,just as an indicator,IF you keep temp at 60c or so....I have had 6 6950's since 2011 (sold em all on ebay last year) that never died,just a few fans & I found fans in china cheap & worked well.

Got a 7970 I bought in early 2013,still mining fine & no issues,it's a keeper,lifetime warranty 

So,the only issue you MAY run into is the fan dying,which if you look around you can eventually find...or do an ebonic engineering feat by being creative with zipties or whatever attachment device & a soldering iron