Those temps are very high, really when its under load you want to be running at about 55C, idle should be 35-40C with good cooling.
If you're using the stock heatsink/fan, then I would highly recommend firstly 1)reapplying the thermal paste but secondly, if that doesn't bring the temps much lower, then buy a third-party cooler that will bring the temps down further, such as this:
http://www.ebuyer.com/product/245376
How many fans are in your system? Are there fans in the rear/top of the case to draw airflow through the case and out the back?