I took all your suggestions and instead of buying an Athlon II x4 640, I got a Phenom II x4 955 black edition. What do you think!!!!!!!!
My system specifications are:
AMD Phenom II x4 955 BE
Asus M4N75TD 750a SLI
Corsair XMS 3 4gb 1600Mhz
500W psu (will upgrade it to a Corsair GS 800W PSU)
geforce 9500gt 1gb (will upgrade it to a GTX 460 or a 560)
LG DVD RW
but I have one issue. My 4GB ram is running at 1066mhz when I saw my bios settings. please help me
You need to set the speed, timings, and voltages manually in BIOS, your board looks to the RAM to get the SPD settings, since those sticks require 1.65V at 1600MHz, their out of the box stable settings are probably 1066 which is why your board defaulted to that, you should have no problem setting them higher.
Its got an nVidia chipset so the BIOS is likely quite different, but look for an AI Tweaker tab in BIOS, in there you should be able to find some DRAM voltage and timings options, it will be in there. You may have to enable AI Tweaker or something to get the menu to show you all the options for tweaking settings.
Check using CPU-Z in the SPD tab and write down the timings and voltage it says for 1600MHz, when you go into the AI tweaker tab it should match up pretty well, make sure you change the voltage too or its not likely to be stable.