PowerLogix G4 Upgrade CPU and Mac OS X

There is nothing quite like an engine replacement to boost horsepower. The PowerLogix PowerForce G4 ZIF 550MHz upgrade CPU for Macintosh G3 towers is no exception. Combine it with Mac OS X, and you get a winning team.

PowerLogix has been making Mac processor upgrades for a while. I do not recall how or through whom PowerLogix got recommended to us. Nevertheless, in a word, this upgrade gets two thumbs up from me.

The lucky candidate for this project was a Blue & White G3 with the Yosemite system board and copper CPU. Other World Computing got our order, and, together with FedEx, it was a painless - and fast - shopping experience. Installation of the new PowerForce G4 processor was fairly painless also. I read the manual cover to cover before opening anything. I discovered that the manual didn't correspond precisely with the hardware that we had purchased. My suspicion was that the manual was written for the previous generation of CPU upgrade. Anyway, I was still able to do the procedure properly. A PDF version of the product manual is available online.

This procedure can be seen as four distinct parts. These are:

1. Firmware updates;
2. Hardware installation;
3. Mac OS 9 software;
4. Mac OS X software.

Firmware Updates

Like previous firmware updates, you need to boot into Mac OS to perform this one. Get your latest firmware from Apple. If necessary, add the word "firmware" to the search engine. Feel free to do this firmware upgrade as required. You can check Apple System Profiler to determine your current boot ROM version before you start.

Now that you have the latest firmware installed on your G3 and are booted into native Mac OS, patch the binary with PowerLogix's utility, found on the included CD. Here's how. The patch utility is called G4 Firmware Updater. Your firmware binary is called G3 Firmware. Copy the two into one folder, any folder. Open that folder and run Updater. It will crunch your firmware binary file and go from there.

Like the earlier update, to flash the update you run the updater, then reboot and press the programmer's button on the front-right of your Blue & White G3 tower (or the appropriate trick for your machine), holding it in after the Apple chord and until the end of the solid tone.

What about this patched firmware? Well, if you leave your original CPU in, your Mac will work as before. No problem. But without this update, your new PowerLogix CPU will crash on boot. Could you reinstall the unpatched Apple version of the firmware if you wanted to? Possibly, but possibly not. There was no opportunity to test this. Anyway, the patched version works flawlessly with either CPU.

Hardware Installation

You'll have figured out already that this gadget is a static-sensitive device. Take the usual precautions. I like to make sure my arm or something is touching the computer's chassis before I reach into the static-protect bag. The heat sink is standard stuff. It may take some careful persuasion to undo the clip; I used two tools for this job, one to push down, one to pry out. Lay the heat sink aside.

Now release the CPU socket lever out and up. The CPU module will wiggle out effortlessly. The PowerLogix replacement looks almost identical. It will be obvious how it goes in. Gently press it home, then close the lever again. Place the original CPU into the static-protect bag. There is room in the tower's hard drive bay to store this, if you wish. Reassemble the heat sink, giving it a few gentle twists to seat it comfortably. Close the case and you're done!

With any of this, if you feel you need to apply any amount of force, stop and reassess. It's all designed to fit properly, and it does.

I wondered about setting clock frequency for this upgrade, but everything is handled on the new CPU board. You'll notice a rotary setting switch near one corner of the unit; it's used for setting clock frequency. Resist the urge. Take the default.

Mac OS 9 Software Installation

Firmware was definitely the tricky bit. With both firmware and hardware behind us, it's downhill all the way from here on. The next step is to install the Mac OS software, which enables the AltiVec engine while running Mac OS. I actually don't recommend this, because the extensions will cause a problem in Classic mode under OS X. PowerLogix recommends two sets of extensions as the workaround, but frankly I wouldn't go there.

Nevertheless, for completeness, copy the G3/G4 Cache Profiler application into your System Folder, Apple Menu Items folder. Copy the two extensions AltiVec Enabler 1.0 and G3/G4 Profiler INIT 1.5 into your System Folder, Extensions folder. You can use Extension Manager to enable or disable these two extensions at will. If you prefer, disable them now. Cache configuration can be done perfectly under OS X. If you leave these extensions enabled and Classic bombs later, you can start Classic from the Classic system preference with extensions turned off, run Extensions Manager from there, then restart Classic. You're dancin'.

Mac OS X Software Installation

All you need here is the Cache Control X application copied to your Applications folder. It should be on your CD, though I couldn't readily find it (although I wouldn't discount the element of distraction). This application is handily available as a download.

Start Cache Control X and take the defaults, mostly. The manual points out a couple of tweaks. These are:

System Profile: Good information, particularly CPU temp;
Cache Control: Take the defaults;
Other: Enable Speculative Access on Restart;
Other: Enable Dynamic Power Management on Restart;
Other: Enable Display Splash Screen (okay to disable later).

I ran the splash screen for the first couple of times until I was certain that everything was in order. Then I disabled it. Now the machine boots quickly and works well, and no-one (except you and I) are the wiser.

Once in a while you might run Cache Control X to check on CPU temperature. Our machine runs at a nice 36*C or so. I was a little concerned about the thermal conductivity between the CPU and the heat sink, but I needn't have been. It's cool and steady.

PowerLogix has a note about its products supporting Mac OS X 10.2, a.k.a. "Jaguar". It's obvious that they bought a copy and ran their chips through some trials, all of which passed with flying colors, as their last week's disclaimer could have been summarized in two words: Caveat emptor! I had and have no reason to believe that there will be the slightest hitch when we do Jaguar in our office. We'll find out, though, as our group will be placing a group-sized order for Jaguar imminently. I was hoping to report our experience with this by press time, but my regular Mac dealer pre-sold absolutely every copy. Inconvenient for us, but it does bode well for Apple.

So, as you know by now, Apple launched Jaguar across the nation last Friday night. It looks pretty cool alright. Everyone has some personal reason for doing any particular software upgrade. For some, it's about having the Latest and Greatest. For others, it's a particular suite of features, of which Jaguar is replete. And for a few of us boring types, it's the (sometimes futile) hope of seeing some rough edges rounded, a bit of a performance boost, and one or two bug fixes. The odds of Jaguar satisfying all three groups of people are looking pretty good at this point. Ciao.