Yea C state and EIST are fine I use them at 3.6ghz. Turbo you might still be able to use, depends on your system. If you can, you might as well as it does increase performance. It won't, or shouldn't, help on Prime95 tests since those stress all 4 cores. Turbo is a function that will disable cores and then increase the multiplier to the one(s) still on. 60C is ok but it could be better. Depends on how you OCed it but your Vcore should be 1.15 to 1.17V. Since you must have increased the FSB you really just need a bit more VTT voltage, keep PLL stock. Turn the voltage down, test run Prime95 for at least 10 iterations. If nothing stops, reboot and turn down again... test... repeat until Prime95 stops a core, then go back up to the last voltage.
Note: I'm not sure what the temps are on a stock cooler actually, 60C might be normal. However, I barely hit that at 3.6ghz but with an aftermarket cooler.