GTX 460 won't stop overclocking at stock voltage

[imwithstupid118]

The temps have gone up maybe 1-2C at load from stock settings of 720,1440,1800. I set my core clock to 850, that ran stable in dx11 1920x1080 X8AA in MSI kombustor with a max temp of 70C. Now I've been raising my memory clock and now I'm at 2200mhz and it is still stable. Should I keep raising my memory clock or should I try to go above 850 on the core clock because I haven't tried yet? Again this is on stock voltage, is it odd for it to be overclocking this much?

 

[imwithstupid118]

my bad, wrong section, reposting in OC forum.