I only have the stock coolers ect, is it still okay to do a overclock if so, what / where can ifind details on doing this.. what clock speeds can i hit 'safely' thanks.
As said, don't go beyond the Turbo Boost speed. Even then, Turbo Boost only kicks-in temporarily and running a processor at that speed constantly won't do it (or yourself) any favours.
If you overclock with stock cooler then you should be prepared for 90C. And as for safe speed I wouldn't recommend anything above it's turbo clock speed on a stock cooler.
As said, don't go beyond the Turbo Boost speed. Even then, Turbo Boost only kicks-in temporarily and running a processor at that speed constantly won't do it (or yourself) any favours.