Sorry AI, I don't see any proof at all. Until I see some hard benchmarks I would have to disagree with you. Forum posts are not proof enough for me.
AMD's CPU naming convention reflects a similar Intel CPU speed. I.E an AMD 2600+ is equal to an Intel 2.6Ghz CPU. NOT a 3.1Ghz CPU. Even overclocked to equal a 2800+, the 2600+ don't even come close to 3.1Ghz. I think your confusing the added speed of the nForce chipsets and the dual-channel DDR to be an added speed of AMD CPU's. A false assumption IMO. :P
Your compairing apples to oranges. I would bet an exact setup using the same speed memory and chipsets, the Intel 2.8 would out perform the AMD 2600 with ease. Even overclocked the results would be the same because the 2600 can't overclock to equal the speed of an AMD 3000+ (if there is such an animal). It simply wont overclock that high.
I'll even go one step further... If you had an AMD 2800+ overclocked to reflect 3.1Ghz, you would still be at the same compaired speed of an overclocked Intel 2.8Ghz at 3.1Ghz. What the heck, I'll even go out on a limb and assume your correct. You have a 2600 that you say outperforms an Intel 3.1. I have an Intel running at 3.1.

Your 3dMark scores are only around 300 points higher than mine. HOWEVER, your basing your conclusions using a 9700 pro. I'm using a 9500 non-pro software modded to a 9700 non-pro. If I were using a 9700 pro overclocked as you, do you think I could make up that 300 points???
I guess that remains to be seen since I don't have a 9700 pro. :P
What do you think?