Windows 7 - intel core 2 quad q6600 kentfield g0 and ram

i have 246 mhz ddr2 ram which is 512mhz with the intel core 2 quad q6600 would getting a 800mhz improve computer performance and cpu

Are you asking if you add faster memory will it improve performance or are you asking if you replace the memory?
If you add faster memory and mix it with the slower memory, all memory will run at the speed of the slowest chip you have installed.

Please elaborate on what you have and what you want to do since your System specs state 3GB of ram and you are asking about 512MB of ram.

Also, DDR2 ram is more expensive than the current DDR3 that is the current standard, so I would try not to spend too much money on DDR2 as it won't work with newer systems so you would be basically throwing away your money.

replacing all ram with faster ram will it improve the performance and also the cpu or what

Not much difference - hardly noticable in "real" use. Download and run CPU-Z then post the CPU screen, mainboard screen, memory and SPD screens. Your CPU is quite good at overclocking to 3.2GHz (without OCing DDR2-800 speed RAM).

IF YOU HAVE PC2-6400 (400MHz) RAM then run the multiplier at x8, BUS at 400 yields core speed of 3.2GHz - keeps clocks nice (FSB-DRAM divider = 1:1) and makes the RAM very happy.

Regards,
GEWB