B3@$T

My monitor runs at 60hz and 1080p by default,but if i lower the resolution to 1366x768 i can run it up to 75hz without any overclocking.I overclocked my monitor to 75hz at 1440x900 and everything seems to be working fine,so im wondering,should i try to step it up by changing the refresh rate from 75hz to 80-90 or should i just stick to 1440x900 at 75hz? PS.i only use 1440x900 75hz when im gaming,for everything else i use 1920x1080 60hz.