That's the idle core speeds. I think there are many overclocking tutorials that are better than what I can explain here, but I'll go ahead. I use two software when overclocking, Prime 95 and HWinfo64.
Go to the BIOS and start adjusting BCLK and multiplier bit by bit (do not jump too high). Run Prime 95 for 15 minutes, watch for temperatures (with HWinfo64) and if the processor reaches unsafe temperatures, shut the machine down.
If the temperatures are too high, you should stop where you were before or buy a new cooler. If it crashes without the temperatures being unsafe, increase the voltage a little bit. If the CPU passes the 15 minute torture, you can increase the clocks (by BCLK or multiplier) again.
No CPU is the same, you have...