Download MSI afterburner from here
http://event.msi.com/vga/afterburner/download.htm
then all you need to do is to raise the core clock (shader clock and core can't be modified separately anymore)
generally in little steps of 20Mhz, but when you start from stock you can easily add up 100Mhz and check for stability, then you increase the freq in little steps.
to test stability you can download many programs, one of these is furmark
http://www.ozone3d.net/benchmarks/fur/
download it and run a "burn in test" (leave everything else on default) and check for temperature, always wait till temperature doesn't raise anymore.
if the driver crashes or you notice screen corruption then lower the frequencies a little bit.
if everything goes smooth and card is perfectly stable at that load temperature then raise frequencies a little bit (20mhz approx) and repeat the test.
once the card starts artifacting (screen corruption) then you found your maximum core clock. Do the same for memory clock.
don't raise both clocks at the same time or you won't know which one is causing you problems if they ever occur.
to squeeze more power out of your card you can unlock voltage control from MSI afterburner. procedure is same to finding max core clock.
when you see screen corruption or screen freezes try bumping up core voltage a little bit
(about 10mV each time) until the card becomes stable again at that frequency.
remember that increasing voltage on your card may seryously damage it if you don't know what you are doing. you do it at your own risk. i'd suggest you just play with clocks for now
keep in mind that if you increase voltage you "MAY" have better OC headroom, but that is no guarantee.
