Update: G4 XLR8 Upgrade! After holding back/pulling the story here several times, I see XLR8 has finally officially noted their G4 compatibility/upgrade trade up information. See their press release PDF file for full details. See the Related Links below for my review of the XLR8 G4/400 in a CarrierZIF.

Quite literally, this could be the last CPU Upgrade 'card' you ever have to buy.

The Acid Test: Compatibility and Stability:

Here are the results of initial testing to see how the XLR8 CarrierZIF design ran in three test systems I have here, each chosen for a particular reason :

• PowerCenter Pro - a good test of maximum bus speed since it was designed for 60MHz 604E bus speeds. (Note: 60MHz bus speeds ran fine in my recently resurrected PowerCenter Pro.)

• 9600/350 (aka Kansas/Mach 5 design) - a sore point for many CPU Cards due to CPU voltage differences. The CarrierZIF with XLR8 G3/400ZIF module ran 55MHz bus speeds rock solid with 320MB Interleaved RAM and 60MHz bus speeds with RAM not interleaved.

• Loaded Genesis - 9500 motherboard based with soldered in cache. Picky about cards it likes especially at bus speeds over 45MHz. Only XLR8's 400Mhz card ran at 50MHz bus speeds in this system (see review). So far the CarrierZIF has run 55MHz bus speeds fine in this machine, which really amazed me.

Stay Tuned for a head-to-head shootout as soon as the Powerlogix Z-Force card arrives.

Gary Dailey tells me XLR8 has conducted extensive testing of the CarrierZIF^TM with a wide range of compatible Macs including both Apple and Clone models. If this card is as reliable as their previous 400/200/1MB CPU card design was in my most problematic Macs, I'll be a happy camper.

XLR8 CarrierZIF^TM Specs:

Available Options:

Note: The CarrierZIF^TM is the Universal Upgrade Adapter (no CPU). The MACh Carrier G3 is the Upgradeable Upgrade (G3Z ZIF CPU module + CarrierZIF^TM card).

Software:

Includes XLR8's 'Cache Blasting' Software control. Fully compatible with Mac OS 8.6 and providing the following features:

• Safe Cache Settings and improved user feedback through informative instruction dialogs and process bar during cache testing
  
  
• Automated Startup - Exclusive feature allows the user to set a selected speed from built in list of speeds available, or at the user's option - - thus automatically selecting the fastest and most compatible speed on startup
  
  
• Virtual Firmware - Exclusive software routine/technique that allows G3 Control to execute performance and compatibility routines before any hardware initializes
  
  
• User-Friendly Interface - No requirement for the user to set CPU/Cache speed ratios. G3 Control simply uses choices based on megahertz (MHz) and megabyte (MB). All the mathematical equations are calculated automatically. Custom settings are readily available for advanced users who want manual control of speeds.

Hardware:

• Compatible with the following Apple Macs and Clones: 7300, 7500, 7600, 8500, 8600, 9500, 9600, and UMAX S900 & J700.

• Removable support bar allows use in Apple and low-profile machines like the PowerComputing models (PowerCenter Pro and PowerTower Pro 180 tested here - Powertower Pro 225/250 owners should contact XLR8 for the latest compatibility info.

• Note: The early CarrierZIF cards were PowerBase compatible (based on a review at MacsOnly and owner reports in my Rate Your G3 Upgrade database) - however the latest CarrierZIF/MAChCarriers (as of 10/99) are said to NOT be PowerBase compatible.
  [Note: For PowerComputing owners I suggest you trim the two topside protruding tips of the plastic fan bracket back about 1/8" with a pair of scissors so the bracket slides back in place easily. This does not affect support as the bracket U channel that holds the card edge remains intact. Take a look at this modified bracket photo. It took 10 seconds to trim the tips back.
  

  
  
  

• Bus Speed Range: 40 to 60MHz (UPDATE: see Undocumented settings!)
  
  
• XLR8 has tested and confirmed compatibility with OS X Server in 8500 & 9500 machines. Other models have not been tested as of this date.
  
  
• CarrierZIF^TM package alone includes CPU Card, Heatsink and rubber heatsink/cpu mating surface gasket.
  
  
• Anti-static wrist strap.

The CarrierZIF^TM will be available without ZIF CPU module (including software and heatsink) for a suggested list price of $189. [Update: As of Jan/2000, OWC's site specials has the card for $139.] You can also order it populated with the following XLR8 ZIF CPU modules already installed:

Availability:

XLR8 promises to ship the CarrierZIF^TM on Monday. Site sponsors Bottom Line, Other World Computing and MacGurus are authorized XLR8 Dealers. For a list of other dealers see XLR8's where to buy page.

Notes on Using Fixed Speed ZIF CPUs: Although any ZIF CPU module should work fine with the ZIF based CPU cards, I want to make readers aware that on models that are fixed speed (non-adjustable) *and* are sold for specific Apple G3 models with a note that no motherboard jumper setting changes are required may not be able to run at their full speed. Here's why:

• These types of fixed speed ZIFs are made so that you don't have to mess with jumpers on the motherboard. These have the bus to CPU ratio fixed at the ZIF and the ratio settings on the ZIF CPU card would be ignored. That means in many cases the ZIF won't run at its rated speed with a ZIF Socketed CPU card. Why? here's an example - using a fixed speed 400Mhz ZIF made for a Beige G3 only:

  I.E. The ZIF is made to run at 400Mhz in a Beige G3 (fixed ratio for 66mhz x 6), and the ratio is set on the ZIF and cannnot be changed. It would work (run fine) but the CPU speed could not be set to run at 400Mhz as the fastest bus speed possible on the Carrier ZIF is 60MHz. Therefore it would run at a max of 60MHz bus x 6 (fixed on ZIF) = 360MHz CPU speed. And remember - that's assuming that your Mac could run 60Mhz Bus speeds reliably (many older Macs can't - my Powercenter can, a friends 9600/350 can, but those are exceptions rather than the rule. Even if another ZIF card allows higher than 60MHz bus speeds, it's not likely those speeds will be usable by most Mac models.

• Best ZIFs to Use: Apple OEM Production (from any Beige or B&W G3s), adjustable speed ZIFs with a wide range or ratio settings like Powerlogix or XLR8 (see CPU Cards page for reviews). [Update: due to the interleaved RAM issue and XLR8 comments - I suspect the $299 Other World Computing OEM 366/183/1MB ZIFs may be the 'X' series Motorola ZIFs noted as having an issue with interleaved RAM when used in the CarrierZIF. [Note: Since Apple G3 models (SDRAM) do not interleave RAM, these ZIFs should not have a problem in those systems (as reported by beige G3 owners of the OWC 366MHz ZIF in the Rate Your G3 Upgrade database.)]

Always ask when buying a non-adjustable ZIF for use with the ZIF-based CPU Cards like the CarrierZIF. If the ZIF does not require changes to the Apple motherboards jumper settings and doesn't have a wide range of settings on the ZIF then I'd not recommend it for use with the ZIF based CPU cards for the reasons mentioned above. I'm not sure if Newer Tech's ZIF upgrades have a wide range of ratio settings or not. Some brands may only have 2 settings - one for the 66mhz beige G3 and one for the 100Mhz bus B&W G3. These would not be recommended either.