It will run better, with higher clocks and larger cache. The real question is though, how much better? If you will be running stock speeds (no overclocks), I recommend you check out Tom's CPU charts for a good answer. If you can run the PII email@example.comGhz or higher on your board and cooler, the difference will be well worth the cost. If not, you might regret upgrading the CPU for $100 or so instead of the CPU, motherboard, and RAM for maybe only double the cost of the CPU only. If you're using DDR2, especially cheap, high latency, DDR2, don't expect big gains at stock speeds.