If you are trying to overclock, find out what the highest ghz your cpu can handle from googling/cpu manual. Then increase the multiplier by a bit to reach the desired ghz. However do not set the multiplier any higher than 18, your base is obviously like 260 mhz, and it's multiplying that by 16 so thats around 4.2 ghz. 18 would be 4.7 ghz, depending on your cpu a multiplier of 18 at 260mhz would be near 4.7ghz which is a lot. You also need good cooling to make sure your cpu doesn't fry. If you don't know anything about over clocking don't touch anything and just let it stay at factory shipped clock speed.