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Singing with the Sonnet Encore/ST G4 Duet

In fiction, there’s a genre called "alternate history" that speculates about what might have happened if key historical events had transpired differently. What if, say, England had come to the aid of the Confederacy during the American Civil War? What if Kublai Khan had successfully invaded Japan in 1281? What if Martin Luther had continued to study law instead of unexpectedly entering religious life in 1505? What would have been different?

For the last couple years, I’ve been living a kind of alternate history, but mine has been: What if Mac OS X had never existed? Or, more accurately: What if there was no way I could use Mac OS X? If these scenarios sound like science fiction or the fevered ramblings of a tinfoil-hat-wearing conspiracy theorist, I’m here to say that ain’t so: that was my reality until the installation of a Sonnet Encore/ST G4 Duet processor upgrade.

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An X Upon Thee — In early 2002 I acquired a dual processor Power Mac G4 (QuickSilver) in hopes of joining the Mac OS X bandwagon and enhancing my tiny digital audio project studio. Although I’d turned to the Macintosh in the late 1980s to avoid the fetid heap of technical legerdemain represented by Unix (I never considered using a PC), I realized Apple had reduced my choices to either Unix or Windows, so I’d better get used to it.

I was thrilled with the G4’s performance under Mac OS 9 (since my backbone audio software can use multiple processors), but to my dismay I found Mac OS X an unmitigated disaster. Without getting into the gory details, the operating system frequently failed to install, let alone boot. Applications randomly crashed and misbehaved: even when they ran, programs often ignored typing and the mouse. My Mac averaged less than four hours between kernel panics, and often died only a few minutes after startup. Some symptoms seemed to change with various updates and revisions, but others seemed to change with the weather or the phase of the moon. No matter which way I squirmed or twisted, Mac OS X was unstable to the point of being unusable.

Friends, colleagues, and Macintosh professionals were mystified. No one had ever seen problems like mine. They recommended re-installing, and, when that repeatedly failed to help, replacing my hardware, especially RAM memory.

So I tried everything. My records show I’ve installed Mac OS X 10.2 a whopping 166 times since mid-September 2002; the installations usually didn’t survive long, and Panther wouldn’t install at all. The machine consistently passed all hardware diagnostics, but during 2002 and 2003 I nonetheless replaced my RAM (five times), my hard drives (three times), my video cards (three times), my keyboard and mouse (four times), and my audio interfaces (three times). I even swapped out the core machine four times, arranging various trades for other dual processor systems of similar vintage. (A few Apple employees deserve credit for privately bending over backwards to try to help during this time: you know who you are. Thanks!) Nonetheless, although individual symptoms sometimes changed with these convolutions, Mac OS X continued to flake out while Mac OS 9 ran fine. There was no discernible reason Mac OS X shouldn’t run for me, but there was no escaping the bald fact that it did not. Friends and clients stopped letting me touch their Macs for fear I’d damage them: perhaps I was cursed.

X Times the Silence — It turned out I didn’t much care that I couldn’t use Mac OS X. Until early 2003, professional audio under Mac OS X was mostly a non-starter. Drivers weren’t available for pro-level audio interfaces, and early drivers were insanely buggy. Applications like Digital Performer, ProTools, Cubase, and Logic either weren’t available for Mac OS X or were sluggish, unreliable, or missing critical features. Apple’s CoreAudio digital audio architecture, which first appeared in Mac OS X 10.2 Jaguar, only began to stabilize with Jaguar updates in 2003, and to this day remains a moving target that developers have trouble hitting. Key software I use in most music projects still isn’t available for Mac OS X – a major stumbling block considering I dip into a library of nearly 6,000 projects with alarming regularity. It’s as if Apple said to a novelist: "Sure, Mac OS X is compatible with everything you’ve ever written – just retype it!" Even if I could run Mac OS X, I couldn’t use it.

So, I basically gave up. I’d dutifully try to run (or, as likely, re-install) Mac OS X on Mondays so I could connect to TidBITS servers and staffers might be able to reach me via iChat, but I did everything else from Mac OS 9. I even contemplated chucking computers entirely and becoming a full-time musician. As stupid a move as that would be, at least I can make a guitar work for decades without upgrades!

Composing a Sonnet — Then one day, my Mac OS 9 system displayed a dialog at startup: "The built-in memory test has detected a problem with built-in cache memory. Please contact a service technician for assistance." The error – and its poor writing – never appeared again, even after several dozen warm and cold restarts over a couple weeks. A call to a trusted Apple technician revealed that the error refers to processor cache: if there was a problem, a possible solution was to replace the computer’s processor card. A tiny bell rang in my mind: could some of my Mac OS X instability be caused by intermittent cache problems on the second processor? After all, Mac OS 9 uses only one CPU normally, and maybe my Mac OS 9 audio software didn’t exercise the second CPU in a way which exposed a problem. Mac OS X, on the other hand, is more egalitarian about spreading work across processors, and was perhaps more likely to stumble across a fault.

I was told that even if Apple still stocked dual processor cards for a G4 as "old" as mine, replacing it would be quite expensive. However, purchasing a new machine wasn’t an option, since current Macs can no longer start up in Mac OS 9. So, I decided to investigate third-party processor replacements.

Selecting a processor upgrade for Power Mac G4 systems turns out to entail a complicated myriad of possibilities, and Apple’s indistinct model-naming policy – even within terms like "QuickSilver" or "AGP Graphics" – doesn’t help. (TidBITS has long-decried Apple’s minimalist model naming schemes; see "Macintosh Model Implosion: What’s in a Name?" in TidBITS-485.) Many Power Mac G4 owners are probably unaware of where their model falls in Apple’s product nomenclature, but the specific Mac model can drastically impact the type and speed of processor upgrades options available. For instance, limited upgrades are available for early "Yikes" G4s, and no processor upgrades are yet available for comparatively recent Mirrored Drive Door or FireWire 800 machines. Apple has published confusing product matrixes to sort out Power Mac G4s; if you don’t already know your model, be prepared to crawl around under your desk examining the orientation of certain ports.




Just to make things more complicated, the Uni-North ASIC component in some early AGP Graphics Power Mac G4 models doesn’t support dual processors (although these machines do support single-processor upgrades): Sonnet describes how to determine the Uni-North version; as far as I can determine, the information is applicable to all multiprocessor upgrades for AGP Graphics G4s, not just Sonnet’s Duet product.

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It turns out there are three dual processor options currently available for my particular Power Mac G4: the Sonnet Encore/ST G4 Duet, the GigaDesigns Dual G-celerator, and the PowerForce Dual G4 Series 133, variously marketed by PowerLogix and Other World Computing. Current prices range from $580 for a 1 GHz GigaDesigns G-celerator (overclockable to 1.2 GHz) to around $650 to $750 for Sonnet or PowerForce 1.25 – 1.3 GHz dual processor upgrades, depending on the specific product and vendor.

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Since I’m one of those rare people using dual processors under Mac OS 9, I couldn’t consider the PowerForce Dual G4, which, as far as my research could determine, makes only one processor available to Mac OS 9. I was heartened that none of the music and audio folks with setups like mine had experienced problems or compatibility issues with Sonnet processor upgrades. Some folks also had good experiences with PowerForce and GigaDesigns upgrades, but a handful had experienced digital "crackle" with certain functions (such as ADAT sync). I’m fully aware all things were not equal: these folks weren’t using the same equipment, only one was using the same model Macintosh I do, and some may have tried to overclock the GigaDesigns upgrade (which enables users to set the system bus multiplier by changing jumpers). Nonetheless, the Sonnet upgrade seemed like the best starting point for me.

Although I didn’t truly need it, the Sonnet Duet upgrade would also represent a performance increase, taking my processors from 800 MHz to 1.27 GHz, roughly a 58 percent increase in clock speed. However, expecting that much of a performance boost would be unrealistic: I’d still have the same 256K L2 and 2 MB L3 caches, my system bus speed would still be 133 MHz, and my hard drives, video cards, network, and other systems aren’t going to get any faster. With the exception of some CPU-intensive tasks, I’d expect a performance gain somewhere between 15 and 20 percent for some operations, and no measurable performance difference for work that relies heavily on the Internet, disk access, or graphics performance.

Installation — Another confusing aspect of installing a processor upgrade in a Power Mac G4 is determining whether the Mac has appropriate firmware. Some AGP Graphics, Gigabit Ethernet, and Digital Audio models may need their firmware updated to version 4.2.8. You can find your model’s current firmware revision using Apple System Profiler in either Mac OS 9 or Mac OS X (which lists it in the Production Information or Hardware Overview sections), and firmware updaters are available online from Apple. However, the firmware in Power Mac G4s can only be updated from a Mac OS 9 system booted from a writable hard drive (not a CD!), and you must perform any firmware update before attempting to install a processor upgrade. Further, Power Mac G4 processor upgrades generally support only Mac OS 9.2.1 or higher: if you’re running an earlier version of Mac OS 9 (heck, early G4s supported Mac OS 8.6!), you must upgrade – and possibly update your firmware along the way – before installation.


Physically installing a processor upgrade in a Power Mac G4 entails removing a daughtercard with the existing processor(s) and installing a new one in its place. Although the daughtercard is securely fastened to the motherboard with screws, conceptually this process isn’t much different than installing RAM or a PCI card. However, it involves extra steps because the processors have their own cooling systems, usually with heat sinks (large, finned pieces of metal which dissipate heat) and sometimes even dedicated fans. The specifics vary between G4 models, but removing and installing both cooling apparatus and processors could be daunting to folks who aren’t comfortable tinkering inside a computer. Be sure to read the instructions for your specific Mac model before you start, and if you have any doubts, ask a more-technical friend or a service technician to perform the installation for you. Sonnet’s instructions are clear and well-illustrated, with photographs covering every model the Duet upgrade supports, so don’t be intimidated by all the pictures of hands holding tools: only a small portion apply to your Mac. (Sonnet also provides documentation in French and German in appropriate markets.) The installation process took me about 10 minutes, and I even stopped to take pictures along the way. If you’re curious – or just want to see inside my Mac – check out the URL below.

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Once the Encore Duet was physically installed, little bits of software are necessary under both Mac OS 9 and Mac OS X to fully enable the upgrade (although it does run under each operating system without these software components). Under Mac OS 9, the software enables sleep support; under Mac OS X, the software enables L2 and L3 processors caches (if they’re not already enabled by the Mac’s ROM), and lets the operating system correctly identify processor speeds and cache sizes.

And the Verdict Is… After all these convolutions, was the Sonnet Encore/ST G4 Duet upgrade worthwhile? For me, the answer is a resounding "Yes!"

First, whatever curse I had involving Mac OS X on this machine seems to have been lifted! Mac OS X 10.3 Panther installs and seems to run normally. While I have experienced a handful of application crashes, they don’t seem to be anything more than everyday software bugs: the operating system remains stable and seems to function in the way Apple intended.

Second – and happily (for me) – Mac OS 9 continues to run just fine. In fact, it’s running better than ever. Although never sluggish on this machine, Mac OS 9 positively flies now. The most pronounced performance increases appear in my primary audio production software, where I am seeing roughly a 30 percent boost in some tasks (converting sample rates and formats, etc.) and a startling increase of more than 60 percent for some isolated items (such as some software-based reverbs and effects processing). Although I don’t strictly need this kind of processing power, it’s a bit exhilarating to have it, and I’ve begun tentatively exploring more processor-intensive approaches to some projects.

I do have some caveats, but I must emphasize that – so far as I can determine – they are specific to my machine and not to the Duet upgrade in general. I’ve managed to contact eleven other Duet users, and none of them have experienced these issues, nor has Sonnet been able to reproduce them on their test systems:

  • Restarting or shutting down the computer sometimes fails. The process proceeds normally – applications quit, the Finder quits, the screens go black – but either the machine never shuts down, or the restart chime is never played. Pressing the reset button always restarts the machine in these cases, and the Mac is not of the opinion it was shut down improperly. This problem is rare under Mac OS X, but more common running Mac OS 9.

  • About half the time, the machine fails to restart correctly when switching startup disks (using either the Startup Disk control panel or preference pane). The symptoms appear to be the same as the restart problem above (everything seems to proceed normally, but the restart chime never sounds).

  • It’s almost impossible to put the Mac to sleep under Mac OS 9: either the system hangs, or it wakes back up instantly. In the latter case, attempting to put the Mac to sleep a second time usually crashes the system. Mac OS X does not exhibit this problem.

Again, to the best of my knowledge, these problems are mine alone, or there may still be something funky about my machine. For instance, I use two video cards from two different manufacturers (the original Nvidia GeForce2 MX that came with the system, and an ATI Radeon card), which is not a standard setup. I also have multiple internal hard drives, and am often using FireWire-based audio hardware which might interfere with sleep.

Fortunately, these restart and sleep issues aren’t significant for me. My machine can be tied up with audio processing for many hours, so I don’t have it go to sleep on its own. (Automatic sleep would also disrupt TidBITS automation and nightly backups.) Similarly, my machine doesn’t restart or shut down on a schedule. The restart problem would give me pause if I needed to reboot the machine automatically (perhaps if I configured it as a server); in that case, I’d probably rely on something like Sophisticated Circuit’s PowerKey Kick-off to jump start the system in case an automated restart failed.

< kick-off/kick-off.html>

So, the bottom line: for those of us who still need to run Mac OS 9 – or for whom appropriate software still isn’t available for Mac OS X – processor upgrades are a viable way to not only extend the life of your machine, but also to put some significant additional spring into its stride. My case isn’t even particularly dramatic: imagine converting a 500 MHz or slower single-processor G4 system to a 1.2, 1.3, or 1.4 GHz dual processor speed demon! And for those of us who still aren’t at ease with Mac OS X, a processor upgrade is a great way to extend the viability of an existing Mac without the trouble and expense of buying a whole new system. The Sonnet Encore/ST G4 Duet is giving me access to Mac OS X without throwing away years of my work only accessible from Mac OS 9: until such time as Mac OS X applications have the capabilities I need – or I decide to go play guitar full time – it’s pretty much the only solution for me.

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