The XLR8 CarrierZIF is unique in that it can be upgraded with many different ZIF CPU modules. The base card has a ZIF socket just like Apple's AIO, Beige and Blue & White G3 motherboards, which means upgrading to a faster CPU later is a snap. Your initial card investment is protected far more than a standard CPU slot card which can't have the CPU replaced. The front page of this review and First Look article go into more detail on the benefits so I won't repeat them here. Suffice it to say if you're in the market for a CPU slot G3 upgrade card with a future the CarrierZIF is worth serious consideration. Although PowerLogix has also announced a ZIF based card, as of this date it is not shipping and I have no estimated date when it will be available. That leaves the CarrierZIF as the only card of its kind at the moment and given the results I've seen, Powerlogix has a tough act to follow.

XLR8 supplied this card with the optional XLR8 G3/400Z ZIF module (reviewed here previously). The G3/400Z contained an IBM 400MHz G3 CPU and 1MB of backside cache. The ZIF was adjustable for speeds (Bus/CPU ratios) as noted in the previous review. XLR8 responded to my complaint that the jumpers were hard to remove by saying that future models would have extended 'tails' which would allow them to be removed and replaced easier.

CarrierZIF card w/ZIF Module Installed

XLR8 400Z ZIF Module

After determining settings that were reliable with my Macs (I did not try to push the razor's edge) You couldn't ask for better reliability than I saw during extensive testing in 3 systems over two weeks - zero errors. I fully exercised the card in applications tests, large program CDrom installs, copies to/from the drives and a Retrospect backup without a single error. Take one guess which CPU card I want running in my older Macs (you guessed it).

Speed Settings:

Bus speeds of 40 to 60MHz are supported via XLR8's MVP (Multiple Variable Processing) switch. You can see the red switch in the photo above on the front edge just to the left of the ZIF socket. Remember that to run a 400MHz CPU speed you must run a 50MHz bus speed, since the maximum CPU/Bus ratio is 8X in the current G3 CPU design (later G3 CPUs chips will support 10X ratios I'm told). See the previous page for more information on speeds and read my CarrierZIF Setup Guide for more info.

Important Note: Along with the benefits of a wide range of adjustments comes some responsibility. This card allows setting bus/CPU speeds to rates beyond the rating of the CPU and possibly your system's capability. You need to consider the installed ZIF module's rating and the limits of your particular Mac (don't start out with high settings that have not been proven reliable in your system/CPU module combination).

Overclocking may void the warranty and may not be reliable. Check with XLR8 on their current warranty policy if you plan on overclocking the card and are worried about warranty support. No company can guarantee overclocked speeds or what bus speed will be possible in your system.

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 MP720 or later, 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". PowerComputing PowerBase models have not been tested by XLR8 but I've had one CarrierZIF owner with an OWC ZIF report a problem. Based on his comments I'm not sure about his switch settings, if he removed the L2 cache, etc. I'll update this page as that information is known. 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)

[Note: For PowerComputing PowerCenter owners with the plastic CPU Fan bracket, I suggest you trim the two topside protruding tips of the plastic 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. My PowerTower Pro 180 has a metal bracket and did not need trimming.

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. Dantz (makers of Retrospect) Tech Note 414 reports there is a problem with all pre-Apple G3 systems onboard Ethernet unless you are running the Ethernet extensions from OS 8.6. They also recommend disabling Speculative Processing if you are doing backups or large file copies over a network as a precaution. 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 other G3 CPU upgrades, see the comments on my CarrierZIF First Look page, the CPU Upgrades area of my FAQ and CPU Reviews page.

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.
• PowerTower Pro 180 - after receiving notes on a possible PTP issue (failure to boot from PTP250 owners), I did a quick check with in my PTP 180. With a 50MHz bus speed and interleaved RAM I had to remove the L2 cache dimm but otherwise it ran OK. It would not boot at 55MHz bus (no cache/RAM still interleaved). In this system I also had to remove the L2 cache for other reviews last year (with 45Mhz or less bus speed G3 cards). I've not tried deinterleaving RAM to see if that would allow faster bus speeds in this system.

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 say 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 in my Genesis, 9600/350 and PowerCenter Pro. For other CarrierZIF owner reports, see my Rate Your G3 Upgrade database. As with all CPU upgrades, often times on inquiry I find out there may have been a L2 cache, RAM, speed settings (Bus or CPU speed too high) or other reason from problems but the database is still a valuable tool.

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]

The hardware design proved reliable in use, able to run higher bus speeds that any previous card I've tested and very fast. With stable operation at up to 60MHz bus speeds in some test machines, a unique ZIF socket to allow for future upgrades (a first), I rated the hardware features/design a 9.5.

The next page contains a summary and final comments on the product.