First we go benching with the good old 3DMark2001 SE, most people really liked this one until some problems with the 3DMark benchmarks.. However for comparing the same system with PBE turned on and off these test will do fine I think.
And again we see a small increase, respectively 44 3D mark points.
Now we take a look on the CPU benchmark score from 3DMark2003 (the 3D mark score was identical with 1524 3D mark points in both cases). The CPU benchmark scores 5 points higher.
When we take a look at the 2 CPU tests however we only see a very small performance increase, 0.3FPS more in the first one, and 0.1FPS more in the second one.
In 640*480 it shows a performance increase of 2.2%, in 1024*768 we saw a performance increase of 1.45%. Both tests were done in 32bit colours with maximum detail.
The first result shows us a very little increase in FPS, and the second result shows us about 1% increase in Triangles per second.
Unreal Tournament 2003
And to end UT2003 :
The biggest difference was in 640*480 in the flyby benchmark which shown 2.3% more frames per second. The botmatch benchmarks show in both cases a performance increase of about 1.4%.
Overall these are just some very small to small performance increases you will get from the Performance Boosting Engine. The maximum performance increase was 4% in the CPU score of PCMark2002, all the other performance increase vary from almost nothing to 3%. Turning on this function did not shown me any negative things, so if you have some quality memory and I motherboard which supports it than I really recommend you to turn this function on in your BIOS.