The temperature of the core is pulled from MSI Afterburner with the max reading used after a completed run off 3DMark Vantage and the Performance preset.
The HD 6990 4GB is clearly a warm running card and in this environment that doesn't change. In a case with some structured airflow, though, should see those HD 6990 numbers come down. The HD 6970 on the other hand is getting plenty of air and runs nice and cool.
It will be interesting to see what companies do with aftermarket cooling solutions for the HD 6990 as time goes on. There's clearly some room for improvement.