What is the fastest CPU I can swap into my Dell Inspiron 5150?

I want to upgrade the CPU in my Dell Inspiron 5150, and I want the fastest CPU possible.

I currently have a 3.06 Mobile Intel Pentium 4.

I have a Socket 478 mPGA Dell motherboard.

I know I can't put the 479 pin Intel Pentium M chips in, but what is the best possible upgrade?What is the fastest CPU I can swap into my Dell Inspiron 5150?If this is a laptop forget it.You have to switch motherboard too and the cost will be more expensive than buying a new laptop.This is the bad side of laptops.....limited upgrade ability and ridiculously expensive parts and labor.What is the fastest CPU I can swap into my Dell Inspiron 5150?u can't period --- it is a laptop not a desktop