faster processor for G4 iMac...?

Hello all, I have a question for anyone who can help: I have an old G4 iMac, and quite simply I am wondering if it is AT ALL possible to upgrade its Processor. I love this thing and want to make it as modern as I can.

I tweaked it a little to install Leopard, but that ended up making it somewhat slower, and so I'm back to Tiger, and it's running great. I would just like to know if there is someway to make it faster, so that running modern programs will be easier.

iMac PowerPC G4
Processor: 800 MHz
Memory: 768 MB SDRAM
OS: Tiger 10.4.11

Thanks for your help, and have a great day.

Rughead