Crysis in particular will benefit from a CPU upgrade, but you're really expecting too much of the 9600gt. I have the BFGTech overclocked version, a Q6600, and 4GB ddr2-1066 ram, and I played through the game at 720p resolution with mostly high settings, averaged about 30-40 fps, I'd say...
I had to RMA a 7900gt that was getting crazy artifacts even at low temps. After emailling a quick description and screenshots, they had me send it out (at my cost) to them. Received back a new 7950gt because the 7900 was out of production and oos. Total time from my email to new card getting...
Be careful with these--before you start overclocking burn it in thoroughly on something intense to make sure it's stable. Lots of people (myself included) get the Black Screen of Death at stock speeds.
I'd also recommend waiting for better drivers and tweakers (rivatuner is behind) and for the...