If the board is limited to 3200, then that's as far as you're going. Are there any options to go faster in the BIOS? I'd guess that if you manually enter a faster speed, it just won't hold, or set you back to defaults.
It's also unlikely your CPU would enjoy going much quicker either. You can try, you'll just get reset back to default if it doesn't work.
As micky says, try the calculator to tweak the timings.