PowerMac G4 AGP - Recommended Upgrades

This page is no longer maintained

This guide is now obsolete and is no longer updated, since the products needed to upgrade these machines have mostly been discontined. It is left available for information purposes only.


Based on the Sawtooth architecture, the PowerMac G4 AGP Graphics were the first PowerMacs designed around the G4 7400 series of Processor chips. Included was the ATI Rage 128 16MB AGP Graphics card, a significant upgrade at the time from the PCI based graphics in the previous PowerMac G4 PCI Graphics. First produced in Sept. 1999 their production run ended in Oct. 2000. The AGP Graphics G4s included 350MHz, 400MHz, 450MHz and 500MHz single processors and shipped with a paltry 20GB Hard Disk & 64MB of RAM.

For a full listing of compatible products see our PowerMac G4 AGP Graphics Upgrade Guide.

Hard Drives

With today's digital lifestyle, one of the first areas to look at upgrading is your internal storage. Digital Photos, MP3s and Videos take up a lot of space not to mention OS X, Applications and any work files! The G4 AGP Graphics will support up to 3 hard drives. The first 2 located to the back of the tower mount one on top of the other. The 3rd Drive would mount underneath your optical drive, although this is sometimes occupied by a zip drive. Because the G4 AGP uses the ATA66 IDE standard it can only see drives up to 120GB in size.

If you need to install a larger drive volume there is a SATA host controller, the Sonnet Tempo SATA Controller, which allows you to fit SATA drives of any size.

With drive prices as cheap as they are we'd recommend sticking as much storage as you can afford in your Mac - you can never have enough Hard Disk Space.

Now you've got all that great internal storage we'd recommend you think about a back-up strategy. As the saying goes "you only lose your data once without backing up". Either back-up to an External Hard Drive or to removable media such as DVD. There are various pieces of software on the market that can help with back-up, some free and some paid for, that will allow you to make a boot-able volume to restore your system from, should the worst happen!

For a full listing of compatible products see our PowerMac G4 AGP Graphics Upgrade Guide.


RAM, Memory, whatever you call it if you run out of it it's terribly frustrating. System crashes, slow applications, the spinning pizza wheel of death are all signs that you need to give your Mac a memory boost.

The G4 AGP has 4 RAM slots located to the left of the Processor, the chips do not have to be installed in pairs or matched so you can add as you go. Under the later OSs (Mac OS 10.3 or later) the AGP G4 can support up to 2GB of RAM, achieved through 4 512MB chips. Under earlier Operating Systems it will only address 1.5GB of RAM using 2 512MB chips and 2 256Mb chips.

The Mac Mantra is "You can never have enough Memory" and this is particularly true with the Mac OS 10 and image editing applications, such as Photoshop. The rule of thumb for Photoshop is that you need between 3-5 times the size of the file you are working on in free unused RAM. When you consider that Mac OS 10 really likes at least 256MB to itself, if you were working on a 30MB image in Photoshop on 10.4 and had no other applications running you'd need a minimum of 346MB RAM!

Our general recommendation for Memory in the G4 AGP Graphics is that if you have less than 512Mb you don't have enough!

512MB memory modules for this Mac can be found here.

For a full listing of compatible products see our PowerMac G4 AGP Graphics Upgrade Guide.


Processors - The engine of your Mac. The bigger the engine the faster you go. It's a fairly obvious statement but true none-the-less.

The AGP Graphics G4 has been one of the most upgradeable Macs, with a great range of upgrades available. Dual Processors, Single Processors with Cache, without Cache; it can all be a bit confusing so let's try and separate it out a bit.

Dual Processors

2 processors are better than one. As a generalisation it's fairly accurate. OS 10 has the capability to use 2 processors as do pretty much all OS 10 Apps. OS 9 has less support for Dual processors and some OS 9 applications will just use one of your 2 processors. Worth checking before you chuck one of these bad boys in.

Recommended for -
Video Editing, Audio, 3-D graphics, Higher End 2-D graphics

Single Processors

Well if 2 processors are better than one it must go that a faster processor is better than a slower processor. The newer chip sets used in the today's Processor Upgrades run cooler and faster than the original G4 chip in the AGP Graphics so you'll see a significant speed boost over your original processor. At the more budget end of a serious upgrade, these Processor Upgrades will deliver the performance to keep you going till you get your next Mac

Recommended for -
2-D Graphics, Video Editing, Audio, 3-D Graphics, Web Design


Essentially Cache makes your processor more efficient. The more cache, the more efficient the chip. The Cache sits there and spools the instructions and data through to the processor. Well designed apps and operating systems can run CPU intensive algorithms purely within cache, avoiding having to wait for new data to be loaded from RAM a particular concern on the AGP Graphics PowerMac G4 since this Mac has relatively slow RAM. To sum up: more cache = better.

The G4 AGP Graphics has a bunch of Processor Upgrades available including some Dual Processor Upgrades. It is worth noting that these upgrades require both OS 9 and OS 10.3.5 or later. Also some AGP Graphics machines aren't capable of running Dual Processors at all. Don't worry, there's a handy link on the product page for these upgrades that tells you how to check if your G4 is compatible.

For a full listing of compatible products see our PowerMac G4 AGP Graphics Upgrade Guide.

Graphics Cards

The last key area to consider upgrading on your G4 AGP Graphics is the thing that gives it it's name - The Graphics Card. The 16MB 128 Rage card is a bit weedy now-a-days and the later versions of OS 10 demand a 32MB Graphics Card. There are only 2 options for the G4 AGP graphics both of which exceed the 32Mb requirement of 10.4 by some way.

The Radeon 9200 is a 128MB PCI based graphics card and so goes in alongside your 128 Rage card, the upshot of this is that you can now run to monitors simultaneously. The downside is that the PCI bus is not as quick as the AGP bus, and you may already be using its limited bandwidth for other peripherals. This card will run under OS9.2.2 on machines WITHOUT built-in gigabit ethernet (1000Mb/s network port). On Gigabit Ethernet PowerMacs, this card requires 10.2.8 or 10.3.3 or later. As this is a PCI card we would tend to recommended it as a second graphics card.

The Radeon 9800 is an 256MB AGP based graphics card, and would replace your ATI Rage 128 16MB card. The 9800 will only run in Mac OS 10.2.5 or later. It will allow you to attach DVI or VGA monitors to your Mac, and also has an S-Video output.

So there we have it, the G4 AGP Graphics, a highly upgradeable Mac.

For a full listing of compatible products see our PowerMac G4 AGP Graphics Upgrade Guide.