you need to access your bios and change these:
CPU rato to 8
FSB Frequency to 400
now you have 3.2... but the catch is.... would it boot?
Making the cpu stable at that speed requires some time and effort. If it doesn't boot, you will need to reset the cmos and try again, but this time you will have to increase your cpu voltage - i'd say an increment of .10volts then test again. Try not to overvolt your CPU - check online the max voltage your cpu can take - you risk your cpu to be burnt if you overvolt it.
Once you can get into windows you need to do a stress test to check if its stable.
If you have 4 banks of 2 GB, then it might be an issue as it will be harder to overclock. You might want to look online for overclock tutorials. There's plenty of info.