Upgrade card maker XLR8 has relesed information regarding XLR8 cards and OS X compatibility. Although Apple had said that the latest OS will not work on upgraded machines, XLR8 states that OS X is fully supported on a number of computer/upgrade card combinations. According to XLR8:
XLR8 is pleased to announce compatibility and support for OS X public beta in specific Macintosh computers. The OS X public beta is fully supported on the Blue & White G3, upgraded with either G3 or G4 Mach Speed Zif?s, Beige G3 systems upgraded with Mach Speed G3 Zif processors and Zif based graphite G4 systems (Non Sawtooth motherboards). XLR8 MACh Speed processor upgrades function perfectly in these systems. Beige G3?s and the OS X public beta may only be run with a G3 processor at this time and the MACh Speed Zif processor upgrades function as normal.
XLR8?s MACh Speed and MACh Carrier and Carrier Zif upgraded PowerMac PCI machines with a processor direct slot (7300-9600 class machines). This class of systems are not currently on the officially supported Apple systems list and in most circumstances the Apple CD will not install onto these systems. Please note that the OS X beta itself states that it is intended for evaluation and development purposes only and warns not to use it in a commercial environment. It also warns not to use it with important data.
Even when upgraded with an XLR8 processor upgrade these systems will not have their caches enabled and until an update is released will run comparatively slowly. XLR8 continues to work towards establishing full compatibility but at this juncture relies on Apple to fully support this class of machines with OS X. New software will be made available for users to adjust the backside cache when operating with a MACh Speed or Carrier ZIF. At this time non Apple supported machines running a MACh Speed or Carrier ZIF card do not have the backside cache enabled.
As with the OS X server version, the final release of OS X client may include the option to perform an unsupported install that will allow older ?non-apple supported? machines to run OS X. With most beta software the final version is often very different, at XLR8 we are continually developing new versions of our products to offer maximum compatibility.
You can find more information at the XLR8 web site.