Raidur :
Did ya miss the review I posted? In supreme commander the difference between quad and dual is less than 10%. Also, in CoH the dual core i3 actually tops a Phenom II x4.
Also take a look at part 2.
http://www.legionhardware.com/articles_pages/radeon_hd_5870_crossfire_cpu_scaling_performance_part_2,15.html
In CoH the E8xxx series C2D massively tops the Athlon II, and Supreme Commander seems to prefer even a faster SINGLE core, as you can see the sempron giving the Athlon II a run for its money.
Sometimes (well in gaming its a LOT of the time) higher IPC is more important than more cores. Once you pass 2 cores anyways. Especially an IPC difference like Athlon II and i3.
Did you read where I stated the difference is in min FPS and slow downs, not straight FPS. Note that this is actually shown in those graphs.
There are no games out there that need straight IPC to be maxed, a 3.2GHz+ clock should do the trick just fine, but there are games that need quadcores. Also with DX11 and Windows 7 we are seeing an increase in the importance of cores.
You can get $70 Athlon II X3s making even the cheapest dual cores irrelevant. So for $100 you can get an Athlon II X4, a Phenom II X3, or an E6600 wolfdale. Obviously, the X4 and the X3 are better deals. For $120 you can get an i3 530, an Athlon II X4, a Phenom II X3, a pretty close tie, except you can get a Phenom II X4 925 or 940 for $20 more, both of which will hang with $200+ quadcores. Anything between $150-$200 is obviously quadcore only territory with the Phenom II 955, 965, i5 750, and the X3440, and soon to be a Phenom II X6 which should clock with the X4s. At the high end, there is absolutely no question of the multi-core dominance.
Are quadcores needed? No. Do people with dualcores necessarily need to upgrade? Probably not. Is there ANY reason to buy a dualcore anymore? No.
This said, don't deny that in a good few games, now, a quadcore will really show some benefit, and in some games, will knock around the dualcores. My 8800 GTS 512mbs are showing some age, though they can play all games on high, not very or ultra high depending on the game, at 1920x1200, I don't go around saying GPU performance greater than dual 8800 GTS 512mbs is useless, it simply isn't true and I don't need to justify my purchases even if I'm still getting great performance or maxing in most titles.