Greetings from Ireland,

I have a G4 Dual 450 which i need to upgrade in Ram and possibly even with a new processor etc.

Can anyone help with the definitave maximum upgrade for this machine in all areas, eg. fastest ram/processor/motherboard etc.,
with best quality brands and suppliers suggested.

I would be most grateful for all expert guidance on this subject.

Max is a dual 1.8 G5 and 2GB of pc100 (use pc133, its cheaper).  Hard drive is limited to 128GB on the slowass stock bus.  Get yourself a sata controller.  Also, you could use a 9600, 9800pro to speed up osx graphics.  All that costs a bunch, cheaper than a newer faster Mac, but not near a fun!

I think my good friend maestro means dual 1.8 G4.  Any ram you get will perform the same pretty much when you're dealing with non-DDR memory.

The cpu upgrade will be the most key component in making your experience good.  If you work with a lot of large files in photoshop or video editing etc. you will be happier with a slightly slower (say 1.33-1.4GHz) upgrade that has L3 cache.  If you do more everyday kind of stuff then get a dual 1.6-1.8GHz that has no L3.  When you work with massive sized files the slower chips with L3 will out perform the faster ones without it but when doing everyday stuff the faster ones sans L3 will perform better.

Oops...type, yeah G4.  Zen is right about the cpus too.  I suggest you check http://www.macsales.com and http://www.xlr8yourmac.com for comparisons of the cpus with and w/o L3 cache.  You could always get one of the 7448 duals and overclock it to 2.0 dual too.  More than likely that would make up for any cache deficiencies.

As far as my G4 goes, I have one of OWC Mercury Extreme processors. 1.0 ghz. They have jumpers on them, and the maps for over and under clocking are very well done. I've had mine up as high as 1.4GHz, but it tended to be unstable there. Backing it down to 1.3 cleared things up though.

Also, the guys over at OWC were very cool when I had to get it replaced. I got a tech on the phone, explained that I was a tech as well, and it was easy as pie from there. OWC = good stuffs.

I agree about OWC.  I have bought memory from them and service was great.  They have a very good rep. in the North American mac community.

I have bought from them several times, and I live in the UK......