This will be sufficient as the paste will spread out. Wiggle the heatsink as you place it over the CPU when you install to ensure better coverage.
My i5-750 was hitting 66 degrees Celsius (Speedfan) whilst under load with the stock intel fan. I changed the HSF to a Coolermaster Hyper 212+ and load temps fell to 46 degrees Celsius, so if you're going to push your CPU it is worth getting a better cooler. It's only about £20.