Although I would not personally see any real advantage to it, the Compaq 610 does have a version featuring the Intel Core 2 Duo T5870 so that upgrade should be possible. I personally doubt it would be fiscally responsible to do the swap but if a good deal can be found on the T5870 it should be doable with minimal issues.
I will recommend ensuring you have the latest BIOS version (version F.20 date: 2 Dec 2011) before doing the swap.