btfc wrote:
Some, not all, depends on rev. #.

The Rev. 2 B&W G3 uses a different motherboard, has an additional drive bracket, incorporates a new IDE controller chip (marked 402) that supports UDMA-33, and includes a faster version of the ATI Rage 128 video card. 350 MHz and 400 MHz models may have either motherboard; 450 MHz versions only shipped from the factory with the Rev. 2 board. The improved IDE controller supports the standard master/slave drive configuration and solves a drive corruption problem. The Rev. 1 board isn't stable with many modern hard drives on the built-in IDE bus because the controller doesn't support UDMA (Mac OS X does an end run around this problem by disabling UDMA on the Rev. 1 motherboard).

A common suggestion in the old days was to put the hard drive on the 16.7 MBps ATA-3 bus used by the optical drive, but the Rev. 1 motherboard doesn't support booting from hard drives on that bus. See the Wikipedia article about the Blue & White G3 for a lot more information about Rev. 1 failings.

When buying a blue & white G3, insist on getting a Revision 2 system. The best way to make sure you're getting a Rev. 2 motherboard is the "402" marking on the CMD646 IDE controller chip. See Accelerate Your Mac! for more details on differences between these motherboard revisions.

Although this model doesn't support drives larger than 128 GB on its main 33 MHz drive bus, the 16.7 MHz bus used for the optical drive supports multi-word DMA 2 and may support larger hard drive.