You'll get your Mac news here from now on...

Help TMO Grow

Subscriber Login

Advertising Info

The Mac Observer Express Daily Newsletter

More Info

Site Navigation

Columns & Editorials
Mac Links

April 14th, 2000

G4 Processor Upgrades

Contact And Other Information
Manufacturer: Sonnet

Product Home Page: XLR8 MACh Carrier G4 CPU upgrade card
Crescendo G4/PCI Processor Upgrade Card

Description: G4 Upgrade Cards
Price: Free
Requirements: PCI PowerMac or Clone
System Used For Testing: Umax S900
256 MB RAM
Sonnet & XLR8 G4 Cards A Great Alternative To Buying A New Mac

XLR8 MACh Carrier G4 CPU Upgrade Card
Sonnet Technologies Crescendo G4/PCI Processor Upgrade Card
by Bill Troop


We Love You Sonnet, We Love You XLR8

Those of us with 6-slot PCI Macs and Mac clones live in dread of the day we'll have to give them up. That day is still far off, thanks to the new generation of G4 accelerator cards. We tested two models from Sonnet and XLR8 with similar specifications: G4 processor running at 400 Mhz with 1MB of backside cache running at 200 Mhz. The main difference between the cards is that the XLR8 offers a ZIF-upgradeable processor. The ZIF slot lets you easily upgrade the processor as faster and cheaper processors hit the market.


Approximate street prices at press time for the cards range from about $649 to $729. Prices fluctuate, so if you are determined to save the last penny, shop around carefully first. Each manufacturer also makes 350 Mhz and 450 Mhz versions of these cards, and Sonnet has a 360 Mhz card to upgrade Nubus systems. You may have to pay a slight premium for the ZIF slot in the XLR8 card, but that will all depend on who is ahead in the pricing game at the time you buy.

We look for things, things to make us go

Another noticeable difference between the cards is their approach to software and customization. Sonnet doesn't want you to see any software, doesn't want you to have any settings you can change. There are no dip switches, and no jumpers. Sonnet wants you to plug the card in and just have it work.

The XLR8 card also works right out of the box. But XLR8 gives you the option of being able to control processor and cache settings (via a control panel), to tweak for higher performance if your system and configuration seem capable of it. The XLR8 card also has dip switches that will allow you to overclock the processor to higher-than-rated speeds if you desire.

Each card performed superbly in our test system, a UMAX S900. These cards will work just as well in Apple Power Mac models 7300, 7500, 7600, 8500, 8515, 8600, 9500, 9600 and Workgroup Server models 7350, 8550, and 9650; all DayStar Genesis models; the Mactell XB-Pro; the Power Computing PowerTower Pro series; PowerWave; and all models of UMAX's J700 and S900 series.

Installation is simple. Run the software, remove the old processor card, and plug in the new one. If your system has a CUDA button, it's a good idea to press it, but that shouldn't be necessary. Sonnet's software fits on a floppy; XLR8's is on a CD and includes some unique items, such as Altivec drivers for Photoshop 3 and 4. We prefer CD distribution. You do need a screwdriver, and an antistatic wrist strap is a good idea too. XLR8 thoughtfully provides both in its package.

Oops, read the instructions

We had an initial problem with the Sonnet card but we must stress that it was all our fault for reading a warning in the instructions and then deliberately ignoring it. The warning states that if you have either an Adaptec 2940UW or a 2940U2W card in your system, you *must* flash upgrade to the latest BIOS. Well, we love Adaptec so much, we have one of each of those cards in our system. The U2W handles the IBM Ultra2 drives we are using at present, and the 2940UW is a bit of overkill for our CD-R and other medium-speed SCSI peripherals. Sonnet's manual doesn't lie. You really must upgrade the flash BIOS, or your system won't work. Upgrading is simple. Just go to Adaptec's website, download the files, and spend a minute running them: an ounce of prevention worth a pound of cure. We tested the Sonnet card first and upgraded the Adaptec cards before we tested the XLR8 card. The XLR8 card comes with software that is said to fix the 2940 problem without requiring you to flash upgrade your 2940s.

Much as we love Adaptec SCSI cards, we also love ATTO SCSI cards. And we've found, over the years, that ATTO cards are notably less fussy about what Mac they're running in and what BIOS version they have. We used our ATTO Express PCI Ultra2SCSI card with both the Sonnet and the XLR8 accelerators. We had no problems.

How they performed

We were very pleased with both the Sonnet and XLR8 cards. There have been problems in the past with upgrade cards -- and it's something of a legend that you're always better off with your original configuration. "If you want a faster processor, you should buy a new computer." These two well-designed cards give the lie to that legend. We found our system was actually more stable than it was with the original 604 processor card. In theory, that shouldn't be possible. But we do exactly the same kind of work day after day. And we've experienced substantially greater system stability with the new G4 cards during several weeks of testing. There can't be any doubt that the upgrade card manufacturers have made tremendous strides in the past two years.

Since our UMAX test system was still using System 8.0, we did three OS upgrades to test the cards for compatibility problems. We upgraded first to 8.1, then to 8.5, and finally to 8.6. Each upgrade was fast and painless. We expected trouble, but we didn't find any.

Speed Improvements

G3/G4 speed improvement over any 604 or 603 processor is phenomenal. What some may find a little hohum is that a G4 doesn't measure any faster than a similarly-rated G3 on Macbench 4 and 5. That's because Macbench doesn't yet test the new Altivec instruction set, and Altivec is the main difference between the G3 and G4 processors. (Apple calls Altivec 'Velocity Engine.') Software that takes advantage of the Altivec instruction set includes the latest versions of Sound Jam by Casady & Greene, Deneba Canvas 7, Macromedia Flash, Director, and Dreamweaver, Virtual PC 3, and DVD Fusion from Sonic Solutions. Terra Soft recently announced their Altivec-capable version of Black Lab Linux. But the main use for Altivec at this time is Adobe Photoshop. Photoshop 5.5 has Altivec support out of the box and XLR8 includes Altivec drivers for PhotoShop versions 3 and 4 as well, written by XLR8's Director of Software Engineering, Chris Cooksey. This is a real boon for the many Photoshop users who prefer versions 3 and 4 of the indispensable but treacly slow image editor. With a G4 and Altivec drivers, there can no longer be any argument that the Mac platform is far and away the fastest environment for Photoshop. We noted improvements up to about 20X on some filters. That's two orders of magnitude! We are in the process of working on our own Photoshop benchmarks here at The Mac Observer. We expect to have our benchmarks ready within the next few weeks, and will publish results at that time. In the meantime, though, the message is clear: if you rely on Photoshop, you must have a G4 processor. And as far as Photoshop is concerned, there doesn't seem to be any measurable difference whether you have a new Powermac G4 or simply upgrade your older processor. Either way, the hours you save in Photoshop will soon make the upgrade worth it.

Macbench 5 processor scores for the Sonnet and XLR8 card were similar within a reasonable margin of error: mostly around 1220 to 1240, or between 22% and 24% faster than a 300 Mhz G3 processor -- about what one would expect, and almost exactly the same as the number we got for the PowerMac G4/400 we recently tested. We ran Macbench in excess of 30 times for each upgrade card.

We found that on the XLR8 card, we could reliably tweak for 2-3% faster Macbench performance by switching the cache speed to 266 Mhz from 200. The XLR8 card comes with an automated cache testing feature that tests your L2 cache memory for maximum workable speed. According to this test, the cache in our card, though rated for 200 Mhz, could reliably perform at 266 Mhz. We tried the setting with no perceived problems. The process takes much less time to do than it takes to describe. While we prefer the feeling of safety that comes from running components at their rated speed, we know many users like to crank the last little bit of performance they can out of their systems. Such users won't be disappointed by the optional configuration features on the XLR8 card, which also allow you to boost the processor speed. We were too chicken to try this out.

Pros and cons

What are the pros and cons of upgrading versus buying a new Powermac G4?

What do you gain by buying a new Powermac G4, rather than upgrading with one of the cards being reviewed here? As far as we can see, there are three principal advantages to a new system:

- faster system bus
- built-in USB
- built-in FireWire

Those are highly desirable features. But their advantages are not overwhelming upon analysis. (We are deliberately ignoring aesthetics. Though the new Powermacs are lovely, we believe our readers prefer to look at their monitors, rather than their CPUs.)

Let's take the peripheral bus first. Although built-in USB and FireWire solutions are theoretically preferable to add-on cards, the USB and FireWire chips that are built into current computers are already nearing the end of their life cycles. USB will eventually have to be upgraded to USB 2.0 (if, as expected, Apple eventually supports it), and FireWire will soon be moving to a new 800 megabit/sec standard and beyond. So everyone with current built-in FireWire or USB who wants the newest USB/FireWire capabilities will have to buy add-on cards sometime within the next twelve to eighteen months. That being the case, we see less and less advantage in built-in FireWire or USB per se. We didn't feel FireWire-deprived on our test system: we had Adaptec's pioneering 8945 combined UltraWide SCSI/FireWire card in our system, and many newer cards are now available.

What about the vastly faster system buses on new Macs? Well, as always, faster is better than slower. But it has been noticed since the first G3 processors with backside cache came out in summer 1997 that the cache magic negates most of the improvement you would expect to obtain with faster system buses. In fact, one of the very few areas where a faster system bus could potentially be useful is when using an Ultra2SCSI or Ultra3SCSI card with a RAID 0 hard disk array that contains at least 4 drives and where it is hoped to approach total throughput of 80 megabytes per second or more. (Note that FireWire is expressed in mega*bits*, while SCSI is expressed in mega*bytes*, so the equivalent FireWire speed would be around 640 megabits per second -- faster than possible with current hardware.) Not many users will ever need to run such a RAID 0 setup.

It remains to be seen how much the performance of the latest video cards is impacted by slower system buses. We suspect the differences are not overwhelming, but expect to have some test results in the future. Thus we find that only certain highly specialized users are likely to experience measurable speed gains by choosing a new G4 system, rather than upgrading their old systems. And there's always that feeling of satisfaction that comes from having a six slot machine. (It is of course nearly impossible to criticize any business decision that Apple has made in the last two years -- who can argue with such phenomenal success? Nevertheless, we fail to see how the sun could possibly stop shining on Apple if it made one high end 6-slot model. Or a 9-slot machine for the creative pros who really need them.)

On the other hand, there is some gain to upgrading an old system. You get your six PCI slots (if you had them to begin with), your built-in SCSI, ADB, and serial -- and save a bundle by not having to invest in new peripherals. You also get a 1.44MB floppy drive. (We confess to using that floppy drive nearly every day, in spite of the known risk that, each time we do, a thunderbolt could be hurled at us by Zeus -- that's Mr. Steve Jobs's kid brother.)


Technical support from both companies is outstanding; it's hard to believe they still make tech support engineers this good. XLR8's is toll-free.


These two boards offer a satisfying, technically sound, and economical way of bringing older Macs into the 21st century. The differences between them were not great enough for us to be able to recommend one over the other. We equally like the simplicity of the Sonnet, and the configurability of the XLR8. We do not find a significant disadvantage to upgrading, rather than buying a new CPU, and are happy to continue enjoying the convenience of a six-slot Mac solution with extensive peripheral support. With an upgrade card, you can apparently have it all.

Final Score (Maximum Score is 5 Gadgies)
4 1/2 Gadgies
(Both Boards)
Pros easy installation
excellent performance
Cons none significant

Today's Mac Headlines

[Podcast]Podcast - Apple Weekly Report #135: Apple Lawsuits, Banned iPhone Ad, Green MacBook Ad

We also offer Today's News On One Page!

Yesterday's News


[Podcast]Podcast - Mac Geek Gab #178: Batch Permission Changes, Encrypting Follow-up, Re-Enabling AirPort, and GigE speeds

We also offer Yesterday's News On One Page!

Mac Products Guide
New Arrivals
New and updated products added to the Guide.

Hot Deals
Great prices on hot selling Mac products from your favorite Macintosh resellers.

Special Offers
Promotions and offers direct from Macintosh developers and magazines.

Browse the software section for over 17,000 Macintosh applications and software titles.

Over 4,000 peripherals and accessories such as cameras, printers, scanners, keyboards, mice and more.

© All information presented on this site is copyrighted by The Mac Observer except where otherwise noted. No portion of this site may be copied without express written consent. Other sites are invited to link to any aspect of this site provided that all content is presented in its original form and is not placed within another .