According to Sonnet G4 machines are also supported but I doubt many G4 owners will take advantage of this upgrade for the time being. Like other high end upgrade cards, the Encore sports a full 1MB backside cache running at 250MHz, a 2:1 ratio. While the G4 processor is capable of supporting a 2MB cache, our past tests indicated the performance gain was not significant enough to justify the additional cost. Sonnet's internal testing of their card returned a score of 1743 under MacBench 4.0. The graph below will give you an idea of the performance gains you can expect in a variety of G3 and G4 machines.
"Sonnet is pleased to announce that our Crescendo PCI and Encore ZIF CPU upgrades will be compatible with OS X. We encourage customers of these products to visit our web site later this summer for additional information and any software that may be available for download."
What is not clear from the statement above is whether the upgrades mentioned are currently OX ready or whether Sonnet simply anticipates having a driver update ready when OS X is released. Either way, Sonnet's Crescendo NuBus, PowerBook and L2 upgrades are not included in the compatibility statement although they support OS 9. Sonnet is committed to extending OS support to as many of their upgrades as is "technically possible." Keep an eye on Sonnet's web site and our Sonnet Upgrade Discussion Forum for up to date information. This forum is moderated by a sonnet technician who may be able to provide us all with more information...