PowerMac G4 SSDs

What particular model G4 Mac do you have? I think only the later MDD models supported cable-select, if you have an older G4 then you need to make sure the drives are jumpered properly. Are you connecting a single drive to each ATA cable into the two ATA-66 & ATA-100 plugs on the motherboard, or both of them on one cable? Each can be a single Master jumpered drive at the end of each cable. Or, the two drives can be jumpered as Slave/Master on the middle/end positions on the cable. MDD can have both drives jumpered as cable-select and put on either position on a single cable, or at the end of the separate cables. Study the jumpering requirements for your particular G4 Mac and maybe check how those drives are jumpered.

You can't use a PC PCI card in a Mac. You need a Mac compatible PCI Card to add SATA ports internally, like the ACARD AEC6290M for example. Or you have to get a PC card ROM flashed for use in a Mac. I am not sure where to find those now.

Why will the PowerMac G4 not accept two SSDs connected to ATA66 and ATA100 cables?

The PowerMac G4's IDE controller can only support two devices. If you are already using one IDE device, such as a CD-ROM drive, then you will not be able to add a second IDE device, such as another SSD.

Does the PCI SATA card require a driver to work with an SSD?

Yes, the PCI SATA card requires a driver to work with an SSD. However, the SIL3114 chipset is not natively supported by Mac OS X 10.4.11. You will need to download and install a third-party driver to use the PCI SATA card with an SSD on your PowerMac G4. There is no official driver available for the SIL3114 chipset on Mac OS X 10.4.11. However, you may try using a generic driver or search for a custom driver such as this.

Additional information:

• The ATA66 cable is faster than the ATA100 cable. It is possible that the PowerMac G4 is not able to properly communicate with the second SSD over the slower ATA100 cable.
• IDE devices share IRQs (interrupt request lines) with other devices. If there is an IRQ conflict, then the devices will not be able to communicate properly.
• IDE devices draw power from the motherboard. If you are adding a second IDE device, then you may need to upgrade your power supply to provide enough power for both devices.

Recommendations:

• If you want to add a second SSD to your PowerMac G4, you will need to use a PCI SATA card with a compatible driver.
• If you are having problems with IRQ conflicts, you can try using a different IDE controller, such as a PCI IDE controller. PCI IDE controllers are generally faster and more reliable than IDE controllers that are integrated into the motherboard.
• If you are having problems with power limitations, you can try upgrading your power supply.