Replacing old processor

[ezgoin]

Hello everyone. Let me introduce myself, I'm ezgoin and I'm new here. I recently bought a used G4 PowerMac with AGP graphics from Ebay and I plan to upgrade it.
I want to start with the 450 MHz processor. In order to do so, do I need to upgrade the Logic board too ? This is my first Mac and I don't know if the logic boards are limited in the size of processor they support like some P.C's are. I don't know the serial number on the logic board nor if it's necessary to knowing processor limitations but there is a number on the corner near the reset button that is KD02305A3HQTD however, all searches don't turn up any information.
I want to install a 1.4 or 1.8 Ghz processor but before I purchase it, I want to make sure that's all I'd need to complete the upgrade.( Besides RAM which I intend to upgrade to 2GB 4x526Mb )
Below is the information listed in the " About this Mac" section of the system profiler.

Machine Name: Power Mac G4 (AGP graphics)
Machine Model: PowerMac3,1
CPU Type: PowerPC G4 (2.9)
Number Of CPUs: 1
CPU Speed: 450 MHz
L2 Cache (per CPU): 1 MB
Memory: 128 MB
Bus Speed: 100 MHz
Boot ROM Version: 4.2.8f1
Any information that anyone would be able to provide me would be greatly appreciated.

[starfireone]

Have you taken a look at the SG4-C1800 from Sonnet Technologies. I believe that it might meet your bill. It is suppose to be a all in one solution. However, I have only look at in the past and did not persude gettting one. But it does look interesting.

[ezgoin]

Thank you for suggesting the SG4-C1800 from Sonnet. However I'm afraid that after looking at in on Sonnet's website that it wouldn't be compatible because it states that it's for the G4 Cube only. I have the G4 tower. They make a SG4-L1800 that if I remember right it said was for towers, however it's been discontinued. That leaves sites like Ebay as my other options which can be iffy at best sometimes.
Thank you so much for your suggestion though, I really appreciate it.