I have been using the Q9000 in my new laptop with 3GB DDR3 RAM, XP SP3 and the GTX 260M GPU and every single game that I have played so far, I have been able to max out at full res (1680 X 1050).
Of course, most games are very GPU dependent anyway so the 2.0 Ghz Q9000 is fine along with my GTX 260M GPU. So many seem to think that the lower clock will translate into lower gaming performance but this is not the case.
I can run GTA IV with a mixture of max and medium settings at 1680 X 1050 at 30 fps, sometimes 40 fps but most of the time about 31 fps. It runs about as good as my Xbox 360 version but looks better in some ways.
Brothers In Arms Hells High way with all settings maxed out at the same resolution, I get 60 fps and that uses all cores. 40 - 50 fps when the action gets really hectic.
Crysis at 1680 X 1050 at high, I get 60 fps , sometimes 50fps, 40 fps occasionally (all cores used), with Supreme Commander I notice that it is using all 4 Cores also, I have all settings high apart from shadows and shaders at 1680 X 1024 resolution. I get 60 fps but I haven't played with huge numbers of units yet so I would expect this to drop considerably.
Wolverine Origins runs at 60 fps maxed out, Saints Row 2 runs 1680 X 1050, medium and low settings, I get 30 - 33 fps but that seems to be even more poorly optimised than GTA IV is, if possible haha. Occasionally I get slow downs to 25 fps when driving.
What I have noticed with the Q9000 is that I can do so much more at the same time and quicker (to be expected) when it comes to applications. Even uncompressing zipped archives are faster. You start making more use of applications where before it would have been too slow to do all at once.