Just make sure you can afford cooling. There's a reason your processor wasn't initially started as a 3.4 Ghz model, but a 2.6 :)
My Intel Core i7 processor has a clock speed of 2.6 GHZ and a turbo boost clock speed of 3.4 GHZ. What is the turbo boost speed used for?
Kind of like a turbo for a car engine. When your computer is under heavy load, the boost kicks in and increases your clock speed in increments towards the max value of 3.4 ghz to increase performance.