Maximum CPU for this laptop?

"The Inspiron 1545 can only accept dual-core Core 2 Duo or Core 2 Extreme chips. A Core i3, of any generation, is a no-go.

The good news is that it can take any Core 2 chip, which means you can install a 3.06 GHz T9900 or X9100 and it will work fine. A T9800 (2.93 GHz) will give it about a 40% performance boost as an example."