>>1
You should probably lurk moar. Learn about overclocking. Or you can just look for an option that says "CPU frequency", it will likely be 166MHz or 200MHz. You'll also want to be able to adjust the VCORE setting, may also be called "CPU voltage". To run faster, it will need more voltage.
First, you want to see how much voltage you motherboard will allow, and how much your power supply can supply. Set the vcore (CPU voltage) as high as you can and reboot (after saving the settings of course). If this creates a problem, unplug things like fans so that they aren't taking too much power away from the processor, then turn the system back on and let it stay on for a while to juice up on power.
After it is ready (don't worry, you'll know), you'll want to go back into the BIOS and remember that "CPU frequency" (may also be called "external CPU frequency" or "external frequency" because motherboard manufacturers won't agree on anything unless you make them) raise that number up (you may get to just type in a number, or raise/lower it with the up and down arrow keys, some BIOSs will make you hold down shift to raise it). Then reboot again (after saving the settings of course), and watch your machine fly through games and benchmarks.
Other info: Your final GHz are determined by that "CPU frequency" multiplied by the CPU's multiplier, which is printed on the CPU, though you may have to scrape some gunk off. If you don't want to do that, you can just go with even numbers (like 200MHz, 300MHz, 400MHz) or increments of 33MHz (333MHz, 366MHz)
Happy overclocking!