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G4 PowerMac Upgrade Guide

This HowTo is aimed at owners of AGP Graphics based G4 PowerMacs (including the Cube). If you are unsure if your PowerMac G4 is and AGP, see below for more details.

Information on upgrading the G3 PowerMacs (also applies to thePowerMac G4 PCI Graphics), can be found in our G3 PowerMac Upgrade Guide. If you have a pre-G3 PCI based PowerMac (eg the 7200 - 9600 range) we also have a PCI Mac Upgrade Guide that might be useful.

For further information on upgrading your Mac, along with online sales of a great range of upgrade products, please visit Second Chance PC Ltd's new webstore,

The G4 PowerMac AGP Upgrade Guide

Follow this link to return to our FAQs and Guides index.

The Purpose of this Guide

This guide is intended to provide upgrade advice to owners of AGP Graphics based PowerMac G4s. It covers processor upgrades, graphics cards and hard drives, along with connectivity issues, upgrading the CD drive and expanding the RAM.

The first thing to make certain of is that your PowerMacis an AGP based one. AGP PowerMacs start off at 350MHz clock speed, however the PCI based G4 PowerMac was also released in 350MHz and 400MHz versions, so if you have a 350 or 400 machine it could be either - you need to check to see if you have any AGP slots - opening Apple System Profiler and checking what type of card is doing the graphics is the easiest way (NB: the AGP graphics machine does have PCI slots as well).

There is also a very useful artical by Apple here, which details all the differences between early PowerMac G4 models.

If your PowerMac G4 is PCI graphics as opposed to AGP you need to follow the same guidelines as for upgrading a G3 PowerMac.

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Why Upgrade a G4 AGP PowerMac

Because it's a lot cheaper than buying a new one, is the short answer. Even the early AGP PowerMacs (with a 100MHz bus as opposed to the newer 133MHz) are very good machines, their architecture can easily support a much faster processor without suffering much "drag" from an outdated motherboard (a problem when upgrading G3 and below PowerMacs).

These PowerMacs are very up to date so they use all the normal interface types of modern computers so upgrading them is easy and relatively cheap.

The alternative to upgrading your current AGP PowerMac is to buy one of the new ones. However, unless you need an absolute top of the range machine, the difference in cost of this is very unlikely to justify the improved performance.

All in all the PowerMac G4 AGP Graphics is a highly expandable machine, and with the range of third-party upgrades available it can keep performing at the top level for a long time yet.

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Processor Upgrades

This is the most crucial upgrade of all, and will make the biggest difference to the overall performance of your PowerMac - assuming you are not chronically short of RAM anyway.

All AGP PowerMacs can take processor upgrades. This includes the Cube, although you may need an additional conversion kit as well.

The main Mac Processor Upgrade manufacturer is Sonnet Technologies. Follow this link for a full listing of all our Mac Processor Upgrades.

Sonnet make the Encore ST range which are compatible with all AGP PowerMacs using Sonnets AutoSwitching technology - it automatically detects whether it is installed in a Mac with 100MHz or 133MHz bus speed and adjusts itself to suit. Check out the Sonnet product configurator for more information on the exact upgrades compatible with your Mac.

One of the first questions to ask is "How far do you want to take the machine?" Do you need a single or dual processor upgrade? These are questions you need to ask. What you need will depend on the type of tasks you will use your Mac for. Do your applications take advantage of Dual Processors? Is there a minimum CPU speed you need to run at? If you are unsure how your computing requirements translate into actual specifications, please feel free to give us a call on 01223 833 412 or an email, our sales staff have a lot of experience in this area, and are always happy to give advice.

These upgrades are very easy to install in standard PowerMacs and come with full, illustrated, instructions. All but the worst technophobes can be confident that they can install the product themselves. The Cube is considerably harder and we would recommend that you think seriously about getting us to install these upgrades for you unless you are confident that you can do it yourself. For all of our Upgrade products we offer an Installation Service. Contact us to find out more.

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Upgrading the Graphics Card

The AGP PowerMac G4s are so called because they have use an AGP (Accelerated Graphics Port) slot for their graphics cards.

AGP was a common standard for graphics cards so this gives you access to a wide range of choice - although you need to be certain you are buying a Mac specific card.

We sell the ATI Radeon range of cards, which have both superb hardware architecture and very efficent Mac drivers - we believe them to be the best cards for the Mac platform.

When choosing a graphics card you very much get what you pay for, the important things are the amount of memory onthe card, the type of RAM used (so how fast the RAM is), the internal architecture of the card and the quality of the software drivers which run it. It is also important to ensure that they carry the correct connectivity for your monitor. Many Graphics card come with different combinations of ADC, DVI, Dual Link DVI & VGA. There are a variety of monitor adapters available to get your older monitor working on a new graphics card or a new monitor working on an old graphics card!

To see the graphics cards we sell, check out our graphics and video page.

Upgrading Hard Drives

All the PowerMac G4s (including the Cube) use IDE internally. IDE was the standard connection used for internal devices, such as hard drives, in most home computers. This means that large, cheap, internal storage devices can be added to your Mac without any problem.

All the G4 PowerMacs have two IDE buses, with the exception of the Cube which only has one. Each IDE bus can support two IDE devices - this includes CD/DVD drives and ZIP drives as well as hard drives. Therefore the total number of IDE devices most PowerMacs can support is four.

If you wish to use more or larger hard drives than your current configuration can support, you either need to go external with FireWire, or you can add a PCI SATA host adaptor , we recommend the Sonnet Tempo Card), which will give you 2 SATA buses. SATA (Serial ATA) is the Hard Drive connectivity used on G5s and Mac Pros. SATA hard drives have a much faster interface and allow you to install much larger drive volumes. Here is a list of our SATA internal Hard Drives

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The G4 PowerMacs are well connected machines, but there a few connections that some of them are missing - both old legacy connections and some modern ones. Please note that the Cube does not have PCI slots and therefore cannot have additional host adaptors added.

  • USB 2.0: There is no real need for this on a FireWire capable Mac, but if you have a particular USB 2 device you need to access then you can add a USB 2.0 PCI card. NB: USB 2 only works under OS X.
  • FireWire 800: FireWire's big brother, this connection is standard on the very latest Macs. On older Macs it can be added as a PCI card. NB needs at least OS 10.2.4 to work.
  • SCSI: Modern SCSI can be fitted to any PowerMac with a spare PCI slot, this can go from a SCSI II to the latest dual channel controller. These can be adapted down to older SCSI if you need to.
  • Ethernet: All PowerMac G4s have ethernet (RJ45), however the older ones have 10/100 as opposed to gigabit ethernet on the later ones. You can add a card to give an older PowerMac gigabit ethernet.
  • Mac Serial: Don't even try using this under OS X, for older OS machines there are cards that can do it, but there do tend to be issues with some of them so give us a call or email if you want advice on this.

If you want any advice on connectivity issues, please give us a call on 01223 833 412 or send us an email.

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Upgrading the CD Drive

Adding a SuperDrive to your Mac is now much easier. If you are running Mac OS 10 then it is simply a case of picking the appropriate specced model and installing it in place of your existing optical drive. If you are running a pre-10 system then it is increasingly difficult to source the necessary Apple parts to allow you to author DVDs

CD Writer

Upgrading the CD drive was one of the great weaknesses of the Macintosh platform. It is certainly possible and there are a number of ways to do it, but the easiest way - adding an internal IDE device - is considerably more difficult (ie expensive) than on a PC. The issue is that Macs running Mac OS 9 will only boot from a CD drive that has a Mac ROM in it, these cost around 4 - 5 times the price of an equivalent non-Apple CD drive. Mac OS 10 is a much more forgiving operating system and as such there are a number of 3rd party drives available.

Our DVD & CD writers can be found on our CD & DVD Writers page

If you want any advice on CD or DVD drive issues, please give us a call on 01223 833 412 or send us an email.

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Memory Upgrades

Having enough RAM is the most important step to take in getting your computer running smoothly. If your Mac jerks repeatedly when doing some task, lack of RAM is the likely culprit. Buying more RAM is the easiest and cheapest way to get more performance from your machine.

Nearly all off the PowerMac G4 AGPs use PC133 SDRAM (can also take PC100), which is commonly available and cheap. The later PowerMacs use DDR RAM which is also reasonably priced and easy to source.

To find the right Memory Upgrade for your Mac why not visit our webstore - On this site we provide a full RAM compatibility guide for your Mac, simply select your Mac from the left hand navigation for a full compatibility guide for your Mac.

If you want any advice on memory issues, please give us a call on 01223 833 412 or send us an email.

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