Obtaining Parts

In working on this project you have two choices for obtaining parts: used or new. New parts are obviously going to cost more but will tend to offer longer warranties. Used parts, however, can save a substantial amount of money, but the disadvantage of having little to no warranty may be an issue for some people.

One of the best sources for used parts is ebay. Keep in mind that used G4 parts can be hard to track down. While you may find all the necessary parts easily, there may be times when several weeks pass before a single used G4 module or other vital component is up for auction. Keep in mind also that the limiting factors in building a G4 seem to be, in order: heat sink, CPU, and logic board. This means there's a plentiful supply of logic boards, fewer CPUs, and very seldom do any Apple heat sinks for the G4 modules ever appear on ebay.

Processors

Processors can be bought new (and sometimes used) at various online vendors such as Other World Computing, MacMall, or Club Mac. New processors start at around $400 regardless of vendor. Used processor modules can start as low as $60. Keep in mind that there are three types of G4 processor modules: PCI daughtercards for the older non-G3 Power Macs (such as the clones), ZIF socket upgrades for the early G3 models and original G4 Power Mac, and the AGP models. You want to focus on the AGP model. These fit in the gigabit, digital audio, and Quicksilver motherboards. See the model comparison page for more information.

It's important to note that the processor module may not include the cooling mechanism. New ones likely will, used ones typically don't. You'll have to either fabricate one yourself (shown on the CPU module page) or purchase a genuine Apple heat sink. Check with your prospective vendor prior to purchase.

You must remember to get a CPU module rated for the board you settle on.  Other World Computing has a nice CPU upgrade help section. For example, the gigabit logic board supports only 100MHz front side bus processor modules. Thus, buying a processor module meant for a 133MHz front side bus won't work well.

For this project, I purchased a used G4 450MHz processor from a seller on ebay. It cost me $149.00 and did not include the heat sink.

Logic Boards

Logic boards can easily be purchased from sellers on ebay or an online reseller such as MacResQ or ShreveSystems. New boards are going to be expensive and I simply recommend getting a used or refurbished one with a warranty. At the time of this writing, refurbished gigabit logic boards from MacResQ were selling for around $149.00 Some people may be put off by refurbished products, however the cost savings can be worthwhile. Quite often a refurbished product never had any defects and was simply surplus left over from manufacturing.

For this project I purchased a refurbished gigabit G4 Logic board (Apple part number is #661-2331, actual number on the board is #820-1153-A) from MacResQ. This should cost you between $125-$150.

Power Supplies

Power supplies can be tricky. The original gigabit boards used a 22 pin power supply to power the motherboard (due to the addition of the Apple Display Connector). Subsequent G4 logic boards went back to the 20 pin power supply design, but Apple's modifications to the wiring mean that a standard ATX power supply from any PC vendor still won't work.

For this project you have two options: purchase a new 22 pin power supply (model number API-9841) from this seller on ebay (if you go with a different model board, the vendor should be able to recommend a source for a power supply), or modify a PC power supply to power your Mac. Since that is beyond the scope of this tutorial, and since there are potential hazards involved, I will not disclose how to do this. A search on Google can help you if this is the method you wish to pursue and you possess the necessary electrical skills.

The beauty of the Apple power supplies is that they will fit in any standard PC ATX case since the dimensions and mounting holes are the same. Keep in mind though, the length of the power connector is 18" and this must be taken into consideration when choosing your case.

For the sake of simplicity I decided to purchase the standard 22 pin power supply. It cost me $75 and will fit perfectly in a standard ATX case.

Graphics

Since none of the G4 models have onboard video the next consideration is a graphics card. If you're not going to be a gamer don't waste the money on anything more than a first generation ATI Radeon. This will give you Quartz Extreme support in Jaguar. Spending any more money on a card is foolish since most games will be held back by a slow CPU. If you go with a new G4 CPU module, you may wish to go with a Radeon 8500 or Geforce 3.

A basic AGP Mac graphics card (such as the standard ATI Rage Pro 16MB) can be found for as low as $10 on ebay. If you want more performance the ATI Radeon will cost about $90, the ATI Radeon 8500 around $180, the Geforce3 64MB DDR around $300, and the Geforce4 Ti4600 around $400.

Another option to consider in the hopes of saving money is flashing a Radeon 8500, Geforce2 MX, or Geforce3 to work in the Mac. You would have to have a PC in order to do this, and the potential for ruining your graphics card certainly exists. Since this is beyond the scope of this project I won't cover how to do it, but there are some sites with information on how to do it.

Since this was just a simple project for me and I wasn't planning on heavy gaming, I decided just to go with an original ATI Rage Pro 16MB card. It cost me $10.

Other Components

Another advantage of this project is that standard PC RAM, hard drives, ZIP drives,  and CD-RW or DVD-RAM/ROM drives can usually be used to reduce overall cost.  Hard drives and RAM are nearly 100% cross platform.  

On the other hand, non-Apple CD-ROM, CD-RW, or DVD-ROM drives can be touch and go. One version of the MacOS will support it, then subsequent updates won't. Most non-Apple drives are non-bootable, but will function just fine once the OS is loaded. In my experience drives made by Lite-On, GoldStar/LG, and Sony tend to be the most cross platform. These drives will usually work with both the DVD player applications and with the built-in burning software in OS 9/OS X. You might want to check the drive database at xlr8yourmac to see if the drive you wish to use is known to work and/or what issues you might encounter.

Also, most standard PC ATX cases can easily be customized to accommodate the Power Mac logic boards. I would recommend getting the case locally due to shipping costs. Keep in mind that the distance from the power connector on the logic board (which will be at the bottom) to the power supply mounts needs to be less than 18" due to the length of the power harness. I would stick with an ATX case that is around 18" high. This will usually give you 3 full size drive bays for CD-ROM/DVD drives and 3-4 half size bays for hard drives.

It is important to note that if you decide to use your own PC case the Airport antenna won't work. The Airport card will still function in the logic board, but the antenna is an integral part of the G4 case. You'll have to either consider a different approach for wireless networking (such as a PCI card and PCMCIA antenna) or find a spare Airport antenna for the Airport card.