How do you replace or upgrade the hard drive in the Power Mac G3 models? Do these models support "big drives"?

Upgrading the hard drive in Power Mac G3 models is fairly quick and straightforward. Information regarding the internal hard drive interface and number of drive bays is provided on the specs page for each system, but also is provided in a chart below.

Platinum -- or "Beige" if you prefer -- Power Mac G3 models primarily shipped standard with a IDE/ATA-2 hard drive although they also have an internal SCSI bus (up to 5 MB/second). Some configurations shipped with Ultra/Wide SCSI hard drives and corresponding PCI cards.

Blue & White Power Mac G3 models have onboard support for two Ultra ATA/33 (ATA-4) drives, but because the Ultra ATA standard is backwards compatible an Ultra ATA/66 or ATA/100 drive also works in these models, just at the slower speed. It could prove to be challenging to track down a pre-Ultra ATA/100 drive as well.

By installing a PCI card, all of the available 3.5" drive bays can be occupied by hard drives and additional types of hard drives -- SCSI or SATA, for example -- can be installed as well.

No Power Mac G3 models support hard drives larger than 128 GB using the onboard ATA controller without a third-party driver such as the one from Intech. The onboard SCSI controller does not have this limitation.

To boot MacOS X, IDE/ATA hard drives larger than 8 GB also must be partitioned so that the operating system is contained within the first 8 GB. Modern third-party controller cards additionally will allow one to get around the size limitation.

Technical details, as well as direct links to PDF installation instructions from Apple replacing the original drive follow:

PM G3	Int. HD Interface	Drive Bays	Instructions
Desktop	IDE/ATA-2 & SCSI	2 3.5", 1 5.25"	PDF
Minitower	IDE/ATA-2 & SCSI	1 3.5", 3 5.25"	PDF
All-in-One	IDE/ATA-2 & SCSI	2 3.5", 1 5.25"	PDF
Blue & White	Ultra ATA/33†	4 3.5", 1 5.25"	PDF

* An Ultra ATA/66 or Ultra ATA/100 drive also works in an Ultra ATA/33 equipped Mac, just at a slower speed.

For complete details regarding drive bays in all models, including the intended purpose for each and which are occupied by default, please refer to the applicable specs page for the model of interest.

OWC has hard drives for sale compatible with Power Macintosh G3 models. Site sponsor Operator Headgap Systems also has compatible hard drives available.