I have 4 dell dimension 5150's and would like to upgrade all 4 to the fastest CPU possible for that old of a computer.

Would an Intel Pentium D 945 3.4 GHz LGA 775 CPU SL9QQ 4M/800 Presler Dual Core work?

They now have PROCESSOR, 524, 3.06, 1MB, PENTIUM 4 PRESCOTT DT, G1

Or what is the best I could get in these?

I've got windows 7 and hoping to be able to get on up to 10 but the 524 is not compatible.