First time overclocking - need help!

Hello y'all,

I just started overclocking for the first time with my E4300 and a GA-965P-DS3. I increased the FSB to 300 and which means I'm on 2,7Ghz. But whenever I'm playin games I get the BSOD or it just hangs. This is because I didn't raise the voltage isn't it? If so, what voltages should I raise and to what?

Edit I also set my RAM at 400Mhz. (*2 because it's DDR2 right?) with the timings 4-4-4-12. This is also what it's rated at, but for some reason it wasn't actually set like this by default. (It's PC6400 Cas 4 Kingston HyperX RAM, 2*1GB) Should I also increase voltages here? If so, which and to what?

Kind regards,
Tim0