P II x2 550 vs P II x4 945

wow, i might be a good person to answer you. I have owned both the 945 and the 550. My 550 wasn't stable as a quad, but still performed quite well as a dual. IMO, the 945 is better just because it is a quad (deneb), i guess if your 550 will unlock then people may say that is better, but the odds are against you for that, and my 945 oc'd to around 3.75Ghz stable.

Performance wise, (with the 550 unlocked) They will work out to be the same. They are, after all, the same chip.

Sure the 550 has a 100mhz lead on the 945 but you're not guaranteed an unlock of all cores. Remember that.

If you don't need to multitask, the 550 is better because it is cheaper and easier to overclock.

And the 550 can multitask. I often play games, with WMP12 and browser open, plus a Linux VM running and my system never slows down. (Mine is not unlocked to a quad).