Update: Undocumented Bus Speeds: I've posted a page of undocumented CarrierZIF bus speeds (60-66MHz). XLR8 probably doesn't support this and these speeds will not be reliable on most macs (Powercenter Pros are a possible exception). Bus speeds add little to G3 card performance so concentrate on reliability.

Update: G4/XLR8 News! 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. Better yet - read my review of the XLR8 G4/400 - the first G4 upgrade independent tests anywhere!

XLR8 is the first (and only so far) company to ship a CPU Slot G3 Upgrade card with a ZIF (Zero Insertion Force) socket design, beating the earlier announced PowerLogix Z-Force to market. I want to say right up front that after two weeks of use in three different Macs here (PowerCenter Pro, 9600/350 and Genesis), the XLR8 CarrierZIF^TM is the best G3 CPU Slot upgrade card I've tested to date. It has been stable, reliable, runs at high bus speeds, has great control software and the unique (so far) ZIF socket feature to allow upgrading the CPU. XLR8 seems to have really done their homework on this design, covering all the bases and it shows. Other than having to remove the L2 cache dimm in my PowerTower Pro 180, it ran fine at 50Mhz or higher bus speeds in every Mac I tested, including 55MHz bus speed with interleaved RAM in my 9500 based Genesis machine.

After some initial rumors of potential problems with interleaved RAM when used with some Motorola ZIFs, I was glad to see reader reports in my Rate Your G3 Upgrade database that the card works with the 'X' series Motorola OEM ZIFs sold by OWC although I have not tested those ZIFs personally. My review is based on using the CarrierZIF with the supplied XLR8 G3/400Z ZIF and also an OEM Apple ZIF from a Beige G3 (compatibility test only). Other OEM and adjustable ZIFs are compatible with the card as well.

ZIF Note: I do not recommend you buy fixed speed ZIFs made to 'drop in' with no jumper changes in the Apple G3s - Why? Because those modules have a hard-wired Bus/CPU ratio on the ZIF module - set with the assumption that the bus speed is 66MHz. That means you will not be able to run the ZIF at its full rated speed. There are plenty of ZIFs to choose from (Apple pulls, OEMs, XLR8 and PowerLogix adjustable ZIFs, etc.) but I wanted to make you aware of which to avoid.

What's Special about a ZIF Socket Card?

As mentioned in my First Look at this card, there are many advantages of a ZIF socketed card such as:

• Lower Cost Upgrades: Only the ZIF needs replacing so you don't pay for the base card over and over again.

• Choices: You can buy the best design base card and choose from anyone's ZIF upgrade to use with it. But as noted above, Apple or OEM (original equipment mfr) ZIFs and Adjustable ZIFs work best, not those that have fixed ratio (bus/CPU) on the ZIF itself)

• Recycle ZIFs: Own an Apple G3 or know someone who does? There's your source for future upgrades. Some real bargains are possible from those trading up to faster speeds. If you own both an older Mac and Apple G3 series, then it's easier to justify an upgrade when two systems could benefit by reusing the previous ZIF module.

• Easier to Repair: If the CPU or cache should ever fail, you don't need to replace the entire card. The reverse also applies of course.

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

The motto of the CarrierZIF^TM is 'the Upgradeable upgrade' which means this is an upgrade that you'll not outgrow like the standard CPU cards. Thanks to the ZIF socket, future CPU upgrades are easy and should also cost less since there are a myriad of ZIF CPU offerings for the Apple G3 systems (and recycled ZIFs from those systems). For owners of CPU card slot Macs, the CarrierZIF^TM may be the last upgrade 'card' you ever have to buy. Since there are rumors of a 10X ratio (bus to CPU ratio) G3 CPU due to arrive this summer, with the CarrierZIF^TM your base card investment will not need to be replaced to use these, only the ZIF CPU module. If I had a 10X G3 CPU module for this review, my older Macs could have been running as high as 550 and 600MHz CPU speeds, since I was able to run 55Mhz (9600 and Genesis) and 60MHz (PowerCenter Pro) bus speeds reliably with this card.

Compatibility:

The CarrierZIF is listed as compatible with the following Mac models [updated 6/16/99]:

• Apple: 7300, 7500, 7600, 8500, 8600, 9500, 9600
• DayStar Genesis, Millennium
• UMAX S900 & J700.
• Power Computing PowerWave, PowerTower Pro, PowerCenter, PowerCenter Pro, PowerTower
• 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 are said to NOT be PowerBase compatible.

I've tested with a PowerCenter Pro (fully tested - but disable 7200 Graphics Accel. extension as noted in the FAQ and PF G3/Powercurve tips pages) and PowerTower Pro 180 (initial boot/checkout tests at 50MHz bus) here successfully, but there might be an issue with PowerTower Pro 250 models based on two reports (one common factor in reported problems was motherboards marked as model "PCC- 5000-0141-01". Until the cause for the reported problems is determined, I cannot recommend PowerTower Pro/PowerBase owners use this card. Note the PowerTower is a catalyst design board, different than the PowerTower Pro Tsunami design motherboard. Check my Rate Your G3 Upgrade database for XLR8 CarrierZIF owner reports (selectable by Mac models)

I also verified that Retrospect 4.0 backups were error-free. With 'Speculative Processing' disabled a complete backup of a 1.2GB boot volume in the Genesis completed without errors (including verification). The XLR8 control panel default setting for 'Speculative Processing' (often called Branch Prediction) is disabled and on the applications performance page you'll see in some cases that setting actually increased performance. Retrospect was the only application I saw that required it, but there could be others that I've not used. I have not tested Adaptec wide SCSI card compatibility but XLR8 has a Tech Note on how to use their software with these cards. The tests in the PowerCenter Pro using the OEM 2930B showed no problems. More information on compatibility issues with G3 CPU upgrades, see the comments in the First Look or in the CPU Upgrades area of my FAQ and CPU Reviews page.

Review Tests/Ratings: I rated this upgrade on a scale of 1-10 in each of the following categories:

1. BenchMark Performance: MacBench 5.0 and Bytemark DR/3 scores of the card under test. Other system scores are shown for comparison.

2. Applications Performance: How the card did in several CPU intensive tests like Infini-D rendering, Bryce 2, etc.

3. Software Controls: Ease of use and features of the supplied software controls.

4. Docs/Installation: How clear and complete the installation and setup instructions are in the supplied manual. Includes general installation info.

5. Specs/Design: Features and details on the hardware design. Includes compatibility information.

6. Summary: Final comments, ratings summary and pricing/availability.

System Compatibility/Stability Tests:

Here is a summary of my tests to see how the XLR8 CarrierZIF design ran in three systems 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. The CarrierZIF ran 60MHz bus speeds with no problems in my system. I had previously removed the L2 Cache dimm when running another brand of CPU card. The PowerCenter Pro used the 2MB onboard video (ATI Mach64) and had 80MB of RAM, running OS 8.1.

• 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. The 9600/350 system has a Radius Thunder3D graphics card, Game Wizard Voodoo2, Jackhammer PCI SCSI card and TurboMax IDE card. Tests were run using OS 8.1.

• Genesis - This 9500 motherboard (w/512K soldered-in cache) based system has always been 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). The CarrierZIF ran 55MHz bus speeds fine in this machine, which really amazed me. The Genesis system is loaded with dual ATTO SCSI cards (slots 1 and 4), IXMicro IXMicro Ultimate RezUltimate Rez (slot 6), FUSE capture card (slot 5), boot UW Cheetah disk and 4-drive RAID 0 array. Tests were run using OS 8.1.

I was glad to see this card is as reliable as their previous 400/200/1MB CPU card design, one of the best CPU slot cards I'd tested previously. I can saw without a doubt I consider the CarrierZIF at the top of the heap of CPU slot cards based on what I've seen in two weeks of use.

Test Systems Hardware Summary:

• Apple PowerMac 9600/350 (Mach 5):
• 320MB RAM (two stock EDO 32MB, two pairs of 64MB FPM Dimms)
• Stock 4GB Hard Disk
• Radius Thunder 3D PCI graphics card (bios/driver v1.07)
• OS 8.1, 4MB Disk Cache, VM off, QT 2.5, QD3D 1.5.3, [No Libmoto]

• Daystar Genesis (9500 Mb based):
• 512MB RAM (matched pairs of 64MB FPM Dimms)
• Seagate Cheetah UW SCSI 4.5 GB HD (ST34501W)
• ATTO PCI SCSI card (2 cards installed to drive boot Cheetah and a 4 HD raid stripe set)
• IXMicro Ultimate Rez graphics card (driver v1.02)
• Aurora Fuse Video Capture card (drivers disabled during tests)
• OS 8.1, 4MB Disk Cache, VM off, QT 2.5, QD3D 1.5.3 [No Libmoto]

• PowerComputing PowerCenter Pro:
• 80MB RAM
• Stock 2GB IBM narrow UltraSCSI drive
• OEM Adaptec 2930 PCI SCSI Card
• Onboard 2MB Video
• OS 8.1, 4MB Disk Cache, VM off, QT 2.5, QD3D 1.5.3, [No Libmoto]

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