What makes you think that running a QX9650 @ 2.5GHz and a Phenom @ 2.5GHz along with a decent graphics card ( 8800GTS 512MB for example ) and the following real-life gaming conditions ( 1280x1024 4xAA 16xAF, 1680x1050 4xAA 8xAF, 1920x1440 2xAA 8xAF ) with various games will show any difference between the two systems, and also give the AMD phenom based system a lead ?

It's not going to happen, and it's called GPU Limited scenario ( as real-life gaming is ).
You may test 100 titles...maybe there will be one title where AMD will be 1fps faster...but on most of them it will be lagging behind by a tad ( max 2fps lower )