DaddyG is right on, a 667eb is NOT an overclockers chip, better off with a 550e or 600e, which are setup for 100mhz bus, jumping up to 133mhz bus is generally a piece of cake with either of them, giving speeds of 733 or 800. the lower multiplier chips have the best chance of success, with a 700e at 933 apparently less likely. If you aren't an overclocker, you probably asked your question in the wrong forum. Check the other current threads on this forum for opinions about oem vs retail.