It's Got Dual Turbo-Charged Engines - Does It Pack A Big Thrust? The XLR8 MACh Velocity MPe Dual G4/500 Upgrade Card Reviewed And Benchmarked


by David Engstrom

XLR8 has had a unique approach to processor upgrades - piggybacking ZIF type processor cards onto either a dual processor capable ZIF adapter or processor slot carrier card. The MACh Velocity MPe Dual G4/500 card is one of the first type, utilizing a ZIF type adapter card that fits into the original ZIF socket of your G3 Beige. You don't have to purchase one of the dual processor adapters with both socket filled, however. It's possible to buy the adapter containing only one processor card, with the intention of adding a second processor at a later date. Also can add another G4 processor of any speed - the two processors don't have to have the identical clock speed. Though XLR8 does say for best compatibility you should use one of their MPe ZIF G4 processors, they do admit that "others may work".

What we review below is the the XLR8 card with Dual Processors.

The first thing that strikes you about the XLR8 MACh Velocity MPe Dual G4/500 upgrade card is how burly it is. This two fisted upgrade, complete with two independent fans on its backside, is huge compared with a traditional single ZIF processor upgrade. The G4 ZIF cards themselves are quite petite, but with the dual processor adapter, fans and attendant cables (to feed juice to the fans and the MACh Velocity card & second processor), the packet takes up a lot of space.

XLR8 is playing it safe by providing one fan for each of the processors. Although you can get away with no extra fan when doing a single G4 ZIF upgrade, the extra heat generated by both the extra processor and the adapter card, requires an effective means for keeping the processors cool. This keeps them from misbehaving - there is nothing like a misbehaving processor to ruin your whole day!


XLR8's packaging of their products has always been exemplary. Not only do they consistently have an excellent manual that walks you through all of the steps, but the company goes the extra mile, supplying you with the extra equipment you will need to make the installation as easy as possible. In the case of this upgrade XLR8 includes: a small screwdriver, to aid in removing the original processors heatsink clip, a quality grounding strap (if there is only one thing you take away from this review, we hope it is that you use that grounding strap....your un-fried motherboard will thank you), and a little dab of thermal grease which goes in-between the first processor, and the heatsink that you must install.

Installing the MACh Velocity MPe is a little more complicated than installing a regular ZIF upgrade. First up is to install the software - a control panel that you can use to manually change the speed of the backside cache and other settings. An extension is also installed - which enables the Velocity Engine of the G4, and works with the Control Panel regulating backside cache settings. The control panel also gives you statistics on the operation of the card, such as the temperature of the processor and the amount of the installed RAM, among

Supported Models

Apple: Beige G3 Power Macs (versions are in the works for the Blue & White G3s and the G4s with the Yikes motherboard)

Mac OS 8.6 to OS X (partial) supported

other things.

Before you take the card out of its anti-static bag make sure that you have the grounding strap connected to your wrist and the other end correctly connected to the computer. The way to do this is to first open up your computer. You will have to remove the power cord to "un-roll" the machine and then plug the power cord back into the computer. Then you can plug the grounding strap into the power outlet on the back of the computer. The grounding strap will not do its work if the power cord is not plugged into the machine.

Removing the old processor is a simple process of removing the retaining clip, releasing a lever, and gently lifting the old processor out of its socket. The old processor's heat sink will not be required by the new upgrade so you will need to detach that from the motherboard and remove it as well. Putting the new processor upgrade in is a little more complicated.

Because the adapter card you are installing will cover the floppy drive connector cable, you will need to disconnect this cable from the motherboard. You don't get to plug it back in! This means that you will lose your floppy drive if you opt for this type of upgrade.

The MACh Velocity card slips right into a vacant ZIF socket and should require only very slight pressure to make it seat all the way. If resistance is experienced something is wrong and the card should be realigned. The next step is to attach the clips that hold the second processors heatsink/fan combo in place. The manual goes into great detail about the process of doing this, but I found it awkward and was worried that if I lost control of the high-tension clips, they would go careening across the motherboard gouging its delicate nervous system. I think that XLR8 could have eased up a little on the clip tension and still have achieved the goal of securing the fan structure.

The last step is to secure the power cabling that makes the fans run and which feeds juice to the adapter card.


In general, for processor intensive tasks and tasks that take advantage of the AltiVec instructions (Velocity Engine) of the G4, (Photoshop, CineBench 2000, QuickTime and SoundJam for example), the MACh Velocity MPe Dual G4/500 turned in excellent performance over our stock Beige G3/266 and our reference machine, the Blue & White G3/350. When compared to the stock configuration the souped up Beige machine showed nearly 4 times the speed improvement in some tests (see below).

However when running OS 9.1 and comparing the dual processor upgrade to a single G4 card, speed improvement in most tests was less dramatic. This is because most applications running under OS 9.1 are not dual processor savvy, meaning that they do not breakdown tasks to run concurrently on each processor. The exceptions, in our test suite, are CineBench 2000 (Raytracing), SoundJam and (theoretically) Photoshop. In our testing CineBench was the most dual processor aware program, turning in a score that was slightly 1.7 times better than when the machine was running off a single G4 processor. SoundJam showed between a 20-23% speed improvement over the single processor setup, and Photoshop, advertised as a dual processor aware program, showed very little speed improvement, when operating under a dual processor environment. Either we are not choosing Photoshop filters that take advantage of dual processors, or Photoshop's dual processor prowess has been greatly exaggerated.

According to both Apple and XLR8 not only will the OS itself take advantage of dual processors, but since this support is built into the OS, any Carbon or Cocoa application will take advantage of dual processors as a matter of course. As David Reynolds of XLR8 put it to us "Developers have to do essentially nothing. the MACH kernel [of OS X] is the real reason for this. Carbon and Cocoa applications 'should' spawn tasks, which can then be spread across multiple processors."

At the moment the XLR8 software that drives the MACh Velocity card does not support dual processors when running under OS X. You can still run OS X but only one processor will function (the left one). XLR8 says that this should be rectified within a month or two.

Our ZoneBench Processor scores for the XLR8 card and the configurations we compared it to are as follows:

Beige G3/266/133/512K 76
Blue & White G3/350 100
MAChSpeed ZIF G4/500/250/1MB 163
MACh Velocity MPe Dual G4/500/250/1MB 189.5

Once we got through XLR8's round of beta drivers to the finished version (2.0), stability of the upgrade was excellent.


Who should consider buying a dual processor card at this point? Those that make extensive use of dual processor savvy applications (you know who you are) and those on the bleeding edge that are looking forward to the rush of OS X applications that should appear in the coming year. For the rest of us it might make more sense to purchase the MACh Velocity MPe card with only one processor for the time being.This will allow you to take advantage of all the extra processing power a high-speed G4 processor will give you, while you wait for the OS X situation evolve to the point where adding a second G4 processor will make more sense. Apple has made it quite clear that dual processors are the wave of the future. The dual processor support built into OS X establishes this, and the fact that the next round of Tower machines should sport dual processors, hits it home. So purchasing a dual processor capable upgrade card should position you well for the future.

At $1,279, this dual processor card is pricy ( a single processor version will set you back $769), but is about half of what it would cost you to buy a new dual processor G4/533 computer from Apple. XLR8 also sells the dual processor card at 400MHz ($929) and 450MHz ($999) speeds.

Post your comments on this article/upgrade card on our discussion board below.

Product: MACh Velocity MPe Dual G4/500/250/1MB
Company: XLR8
Rating:  (out of a possible 5)

Hits: Good performance, very stable, flexible upgrade path, forward looking

Misses: Dual processors of limited utility under Mac OS 9.x, pricey, upgrade makes the floppy drive inoperable

SRP: $1,279 .... Check prices at: OtherWorldComputing


"Real World" Tests

The tests below are from our suite of real world application tests. These tests feature a diverse selection of applications commonly used by the Mac community. The test suite was designed to render an accurate and well rounded picture of performance. Click here for detailed information on each test and our machine's configuration. All of the tests below (with the exception of the Quake III & Cinebench 2000 tests) were timed with a stopwatch. The times are then converted to percentages relative to our base Blue & White G3/350 machine which is set to 100%. For all scores, higher numbers are better. Absolute scores for most tests can be found below this section.

Finder Tests


AppleWorks 6 Tests


Quake III Tests
Actual frame rates for all configurations listed below this section.



Photoshop 6 & Other Data Crunching Tests






Encoding/Decoding Tests





Actual Scores - In Seconds except for the Quake (fps) and CineBench 2000 scores


Finder Copy

Finder Copy
(Large File)

AppleWorks 6.0.4

AppleWorks 6.0.4
Find & Replace

Analog 4.1.1 Code Analysis

Quake III
Default Fastest Setting

Quake III
Default High Quality Setting

Base Machine
Blue & White G3/350



17.69 49.95



Stock Beige G3/266/133/512K 34.66 28.13


22.70 63.54



XLR8 MACh Velocity MPe Dual G4/500/250/1MB 32.62 27.37


11.34 35.33



XLR8 MAChSpeed ZIF G4/500/250/1MB 31.92 27.56


11.07 34.26




CineBench 2000
Render Score

CineBench 2000
Graphics Score

SoundJam 2.5.2
MP3 Encode

QuickTime 4.1.2
(Sorenson 2X CD)

StuffIt 6

Photoshop 6.0
AltiVec Filters

Photoshop 6.0
Non-AltiVec Filters

Base Machine
Blue & White G3/350



1045.23 21.89



Stock Beige G3/266/133/512K 3.41



1406.30 31.37



XLR8 MACh Velocity MPe Dual G4/500/250/1MB 11.4 4.02


379.23 18.58



XLR8 MAChSpeed ZIF G4/500/250/1MB 6.68 4.29


365.83 17.41



MACh Velocity MPe Dual G4/500 Card Stats



Cooling System

Variable/Fixed Clock Rate

Tech Support


Current Price Information

MACh Velocity MPe Dual G4/500/250/1MB


e-mail or phone. 770-564-5682 2 Years


Internal Links
External Links
  • MacReviewZone - Processor upgrade reviews