Try using the CPU Stability Test utility found here. After only about 10 minutes of running its 'CPU Warming' function I have found it will heat my Tbird 1-2C more than Prime95 or the Sandra burn-in wizard and 3C or more than a 3D game like Unreal Tournament.
In fact I once ran a 16 bot UT server in a window, the Sandra CPU burn-in wizard, prime95 and CPU Stability Test all at the same time and my CPU didn't get any warmer than when running CPU Stability Test alone.
In fact I once ran a 16 bot UT server in a window, the Sandra CPU burn-in wizard, prime95 and CPU Stability Test all at the same time and my CPU didn't get any warmer than when running CPU Stability Test alone.