Take into consideration the thermal throttling speed, which may be around 93C for 7950s. Keep as far below as is reasonably possible, and just know the cooler you can keep them, the longer your investment will last.
There is nothing WRONG with going up to 90C or staying there, but it is decreasing life span.
I am using this for mining Litecoins. The useful life of this hardware will be 6-12 month max, I guess. So, if it can last that much, it's ok. I am going to install a couple of fans to blow air at the GPUs and see how low the temp will go.