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XLR8 Information FAQ - MAChCarrier G4 & CarrierZIF
Also see FAQ - Nomenclature

1. What is the difference between the MAChCarrier G4 and the Carrier ZIF?
   The difference between the MAChCarrier G4 and the Carrier ZIF is the MAChCarrier comes with an XLR8 ZIF module onboard, as the Carrier ZIF is only the adapter.
   
   
2. What does the MAChCarrier G4/Carrier ZIF offer me as opposed to the many other upgrade cards on the market?
   The MAChCarrier G4/Carrier ZIF offer maximum compatibility with applications and peripherals. With XLR8's exclusive Smart Control with Virtual Firmware and utilization of the ZIF socket introduced on the Power Macintosh G3 systems, the MAChCarrier/Carrier ZIF offer unparalleled upgrade options.
   
   
3. What systems will accept the MAChCarrier G4/Carrier ZIF?
   The MAChCarrier G4/Carrier ZIF will work with the Apple Power Macintosh 7300, 7500, 7600, 8500, 8600, 9500, and 9600 series. They also work in UMAX SuperMac S900 and J700 systems, PowerComputing PowerTower, and the Daystar Genesis MP 720 and up and the Millennium series.
   
   
4. My current Mac has a slower system bus than today’s Power Mac G3s. Will that matter for G4 upgrades?
   No more than for G3 upgrades. Of course, any processor will perform better on a system with a faster bus than it will on a system with a slower bus. On the other hand, the backside L2 caches present on G3s and G4s minimize the importance of system-bus speed. Most of the benefit of a processor upgrade can be achieved even with a relatively slower bus.
   
   What is more important is that your Mac’s system bus speed sets an upper limit on how fast a processor you can install in it. The maximum processor speed supported by a system is the product of two factors: the computer’s rated system-bus speed multiplied by the processor’s maximum CPU multiplier.
   
   For example, consider an old (pre-G3) Power Mac or Mac clone with a 50-MHz bus, upgraded with a G3 processor. Until recently, the maximum CPU multiplier on G3s was 8x; this limited to 400 MHz (50 MHz x 8) the speed at which these older Power Macs could run. Even if you installed a faster G3 in such a system, it would not reliably be able to run faster than 400 MHz. Recently, however, IBM began shipping G3s that support a 10x CPU multiplier. This makes it possible to push systems with 50-MHz buses to run at 500 MHz (50 MHz x 10). Motorola has not yet announced what the G4’s highest CPU multiplier will be.
   
   
5. How fast will it go?
   In theory it is limited only by the CPU multiplier, 7400s (G4s) are limited to a 9 x multiplier so the speed is limited to 450 MHz (9x50). A 7450 has a 16x multiplier, (600 and up MHz) but no one has a 7450 form factor that fits.
   
   The speed of the MAChCarrier G3 and Carrier ZIF can be adjusted by a set of switches on the Carrier daughtercard and a set of jumpers on the ZIF module. A complete chart for all possible settings is included in the manual.
   
   
6. What ZIFs work with the Carrier?
   XLR8 and Apple are guaranteed to work. OWC's are pretty much copies of Apple's, so they work as well. PowerLogix does work, but has a number of version problems. We have had mixed resultes with Sonnet's due to their attempt at "auto" setting the CPU.