10-31-2007, 04:04 AM
What kind of G4 is it? Is it a "Yikes!" machine (PCI graphics, ZIF CPU socket) or a "Sawtooth" machine? (AGP graphics)?
If it's a PCI machine, you can't upgrade it to a dual anything. Fastest you can go is a 1GHz G3 or G4, and I'd recommend a G3 (they're faster for non-AltiVec optimized applications... which is most everything. Or was, last I checked.)
If it's an AGP machine, you can (if you can find a used dual 1ghz sawtooth-compatible card). You can definitely upgrade to dual 1.6s or 1.8s. However, for what it would cost, it wouldn't be worth it. The cheapest new dually card is a dual 1.6 for $380 at OWC.
Adding a decent CPU won't do you any good without a decent amount of RAM-BARE MINIMUM is 1GB, ideally you'd go all the way to two... Tack another $200 for 4 low-density 512mb SDRAM sticks, if you haven't upgraded already.
And even then, your graphics card (if you still have the stock rage 128) won't support any of the accelerated graphics (quartz extreme, core image), which means you'll need to pay up for a decent one. Assuming you don't want to flash one yourself, or gamble on a pre-flashed card from ebay, figure another $130 for a barely passable radeon 9200 from OWC.
Now you're up over $700. Plus shipping. For a machine that may not run Leopard (depending on how it's coded... minimum requirements include an 800MHz G4, but the installer may see that you have a Sawtooth board and refuse to install, even with dual 1.6s), and which will struggle to reach 2/3 the performance of a new, base model Mini with a 2GB RAM upgrade.
So basically... IF the machine can be upgraded (check it out and let us know what model it is), it's still not going to be cost effective to do so. And while that doesn't necessarily mean you shouldn't do it-I'm currently looking at upgrades for my DA G4-it does mean that you need to seriously consider other options, unless you're doing this for fun like I am.