How-To: Upgrade the processor on an older macintosh G4

We began this story by buying an older graphite 400Mhz G4 tower from ebay.de some months ago. The motherboard and the manufacturing of the AGP G4 series, codenamed "Sawtooth", are in our opinion quite good (i.e. there weren't huge amounts of AGP G4's that failed in weird ways over time). After doing some preliminary reading we found that doing a processor upgrade for a G4 can sometimes require messy heat sink paste. Some other mac proc upgrades use the same heat sink provided with your original proc. We decided on a choice that does not require thermal paste and has a larger new heat sink and fan included: the PowerLogix PowerForce47 G4/2.0GHz with 512K 1:1 L2 Cache Per Processor. (note: we were not remunerated by Powerlogix nor did we receive free merchandise for this how-to nor is this article a review of comparable mac proc upgrades). After some trials and tribulations with the processor upgrade, we simply wanted to put this information out there to help who it may, after all we never enjoy seeing macs in the trash.

To start with, we did read the documentation shipped with our Powerlogix upgrade. This being fairly basic in some ways, we were reassured and jumped right in. To save yourself the same hurdles we met, read on.

The documentation's summary of a powerlogix in an agp upgrade:
1. Upgrade the apple firmware of the motherboard (the boot rom) to 4.2.8 or higher.
2. Upgrade the firmware again with Powerlogix's proprietary software.
3. Remove the old processor.
4. Install the new processor.
5. Boot.

Now the actual summary of our difficulties not being the point of this article, we will keep the updated summary short. To be certain, the list above is correct, but rather vague.

Summary of a powerlogix in an agp g4 upgrade should be:
0.7 Make sure you have OS 9 installed on a partition or a harddrive.
0.8 Make sure the harddrive is bootable (harddrive is master not slave) and at least os 9.1.
0.9 Download the apple boot rom updater for boot rom 4.2.8 and copy it to the desktop of os 9.
1. Launch the boot rom updater and reboot in programmer's mode.
2. Upgrade the firmware again with Powerlogix's proprietary software.
3. Remove the old processor.
4. Install the new processor.
5. Boot.

What follows is our step by step instructions. You may also want to refer to Powerlogix's documentation.

Before starting, in OS X, install the CPU Director software from the Powerlogix CD included with your processor.

You must have OS 9 installed and bootable on the machine, even if you only want to run OS X on the computer later. This is because Apple never released a firmware upgrader for the AGP G4 and many other models of the G4 line for OS X. If you only have one harddrive in your computer and that harddrive only has one partition and that partition has OS X installed, you are out of luck. OS X's Disk Utility can not repartition a disk that contains the startup volume. For us, this required that we install OS 9 on a second hard drive. Our computer did not want to install or boot OS 9 if there were any other harddrives in the machine. Also, the single harddrive with OS 9 should be set to master (pictured is our 160 gig hitachi deskstar, check the pin diagram for your harddrive):

Now if you had trouble installing from an official OS 9.2 installer cd as we did, try installing OS 9.0 and upgrading to 9.1. Realize that you must have at least 9.1 installed for the firmware upgrade. When you install your first OS (be that OS 9.0, 9.1 or 9.2), be sure to download the firmware upgrader from Apple's site and copy the Power Mac G4 Firmware Updater and the Power Mac G4 Firmware to the Desktop:

You may now upgrade the OS if you are in OS 9.0. We had trouble with the 9.1 upgrade as well and had to boot without extensions by holding down the shift key when booting. Now because you've already downloaded and copied the firmware patches to your desktop, you don't need to worry about missing extensions for the net or any other way to get those files to your computer. Double click on the Power Mac G4 Firmware Updater.  It will now walk you through the installation and will finally ask you to reboot the computer in programmer mode. When the computer is off push in the programmer key and press the power button.  The programmer's button has a -v- symbol inside a circle and is the concave button on the right under the power button on our G4 AGP. Release both buttons immediately after the long programmer's beep has stopped.

The computer should now show the progress of your firmware upgrade.  When it has completed, eject the CD-rom drive and put in the Powerlogix CD (in our case this cd is labelled "Product Manuals & Installation Videos", but it is also the firmware updater CD).  Once again push in and hold the programmer's button and the power key.  Immediately after the programmer's tone stops, release the programmer's button and the power key and then press and hold down the C key on the keyboard.  You will hear the computer chime the boot sound now.  When the green Powerlogix firmware upgrader screen comes up, choose "4: Install all patches".  (note: This picture shows "Remove all patches" because we have already applied the patch, but yours will be "Install all patches.)

When the Powerlogix firmware updater has finished and the computer has shut down, unplug all cables on the G4 and open the case.  The processor is under the large silver heatsink.

Pop up the heatsink clips carefully and remove the heatsink by gently pulling straight up.

Remove the screws from the processor's card (we had three screws). Set aside the screws, you will be using them in two steps. Gently remove the CPU card by carefully pulling straight up (a bit of a jiggle may be necessary, but don't force).

Place the new processor and heatsink (all connected) on the processor connector. Line up the processor connector carefully (this may require having the G4 at eye level) and gently push down until you hear a click (a bit of a jiggle/rocking motion may be necessary, once again do not force).

Screw in the two screws you set aside into the new CPU.  Try to drop the screws straight down, the cavities in the heat sink are tall.

Connect the power cable of the fan to a free connector on the 12V power of your computer.

Replace the OS X harddrive on which you installed CPU Director above and boot your machine.  If all went well with your install, OS X will boot.  Open the About This Mac window in the Apple menu to verify that your new processor is recognized correctly:

The Powerlogix card we use includes temperature monitoring among other things.  Temperature monitoring is quite important since in our case we went from a 400Mhz to 2Ghz processor. Launch the CPU Director software and choose the "Thermal" tab to see the temperature:

Without the proc upgrade we couldn't run a realtime audio synthesis engine and with the upgrade we can. Nuf' said. We hope your installation process was less painful than ours! Go enjoy your new speedy mac.

[darjama @ Dec 19th 2005 2:47AM]

you mac folks are such sissies. Thermal paste is nothing to be scared of.

[iDriveX @ Dec 19th 2005 2:47AM]

You guys should do a regular "How-To" article each week dedicated to "how-to" all sorts of upgrades on all sorts of machines. I just recently went up to a dual 1.7 Ghz G4 Processor in my G4 Cube. That's a "How-to" and a half right there!

[Conrad Quilty-Harper @ Dec 19th 2005 2:47AM]

Awesome work, this'll be helpful to anyone that want to do this kinda stuff. Personally I'll leave all this tweaking and upgrading CPUs to my PC. I use my Mac to get away from all that stuff!

When I find myself comparing the specifications of different fans for my PC I know exactly what Apple is doing that a lot of the PC world is missing. And I realise why I pay a premium for my Macs. Now, if only my Mac had Battlefield 2. ;-)

[Timmay @ Dec 19th 2005 2:47AM]

I almost did this to a Pismo Powerbook i had. Same idea, it would have been bumped from a G4 400Mhz to a G5 500 Mhz but I didn't see the justification of $300 for what seemed like a small jump. Unlike this one that looks like an awsome way to revive a Mac. But 100mhz FBS? Come on now...

Timmay

[James @ Dec 19th 2005 2:47AM]

What was the real world difference in performance after all that effort?

[Eric Jacobsen @ Dec 19th 2005 2:47AM]

ditto #1... thousands of PC hobbyists are shaking their heads at this

[fabienne @ Dec 19th 2005 2:47AM]

darjama and Eric Jacobsen: in all reality i'm not afraid of heat sink paste, but the powerlogix card has a ton of stuff on the circuit that they include compared to other makers of g4 proc upgrades including their firmware and monitoring software. *smile* however, it may appeal to some people that they don't have to buy anything "extra" to make this work (if you don't count having os 9 on hand, a hard drive you can wipe, and quite a bit of time as things you have to buy).

---fabienne

[nando @ Dec 19th 2005 2:47AM]

Does anyone have any personal knowledge of how hard/worthwhile it would be to upgrade a dual g4 quicksilver? (800MHz)

I've been toying with the idea of upgrading the processors, but honestly I haven't completely justified it. . .what it really needs is more RAM (only supports 1.5GHz)

[Scott @ Dec 19th 2005 2:47AM]

I just tried this with my Gigabit Ethernet Dual 450 - no worky. I was installing a dual 1.6 7447. Must've been a dead processor cause it wouldn't boot. And, yes, I followed the same proceedure you describe above.

To my relief, OWC took the processor back - no prob. But, I think I'll spend the money on a new machine and be happy with what I've got in the G4.

Argh.
Scott

[nando @ Dec 19th 2005 2:47AM]

I just want to point out that the above is a typo. . .I know most people assume that as a mac user I think that RAM is measured in Hertz

[abl @ Dec 19th 2005 2:47AM]

I did the same upgrade. Fortunately my Mac already had the required firmware - I think the upgrade would have gone right back had I had to go through the OS9 contortions. Also the instructions were poor (I like your much better!) and tech support not much help, actually. But now that it's all working, I am glad I did it - good price/performance boost (and no, a new Mac mini would have been a lot more dough once I put in 2GB of RAM, and where would the 3 additional drives have gone? Also a lot more software/OS configuration would have been required). This upgrade was ~$350 ad 30 minutes, a good deal I thought.

[d @ Dec 19th 2005 2:47AM]

What *I'd* like to see is a G5 processor + video card upgrade for the old G4 iMacs (the 'Luxor Lamp' or 'Sunflower' model)... Anyone? Anyone? Bueller?

[tr @ Dec 19th 2005 2:47AM]

for those interested in dual processor upgrades, it might be good to note that sawtooth owners with a Uni-N revision 3 chipset WILL NOT be compatible with dual processors. you can check your revision using this app:

http://www.macbidouille.com/downloads/UniNorthASICChecker.sit

[.; @ Dec 19th 2005 2:47AM]

#4, I think you meant upgrading from a 400MHz G3 to a 500MHz G4.

Something I found when looking into a similar upgrade for a pismo was that the (then top of the line) 900MHz G3 was almost as fast as a similar speed G4....although for things that use AltiVec (like ripping CDs and DVDs) it was slower. I still count the pismo in my top 3 mac systems for its ability to use two batteries at once...up to 10hrs battery life!!

[mveloso @ Dec 19th 2005 2:47AM]

#8: Upgrading a quicksilver is pretty easy. Whether it's cost-effective, well, that's unclear.

The most cost-effective upgrade is probably the PowerForce47, a G4/1.8ghz for $339 (www.macsales.com). You get to keep your hardware & ram, and you probably could get $150 on ebay for your old processor (note: be sure to check the prices, I haven't looked in a while).

The QS machines are pretty nice, much nicer looking than the MDD ones. Plus you can cram three or four drives into it and run a relatively hefty (but kind of noisy) server.

[motech @ Dec 19th 2005 2:47AM]

fastmac has great upgrades as well

http://www.fastmac.com

[Mike @ Dec 19th 2005 2:47AM]

Grr. Great piece, but:

Payed = past tense, releasing rope or line "I payed out twenty feet of slack."

[RX9 @ Dec 19th 2005 2:47AM]

If you have a Power Mac G4 MDD (Mirrored Drive Door) model, there is an OS X firmware updater available, though these machines were pretty fast anyway...

http://docs.info.apple.com/article.html?artnum=120186

[Bhagiratha @ Dec 19th 2005 2:47AM]

Great stuff .... if only I knew how to get to the power supply of my dual 2.5 G5 system, so that I could clean off the dust.

Any ideas anyone?

[Bigfat @ Dec 19th 2005 2:47AM]

It's always a breathe of fresh air to upgrade these old G4's. I remember paying *$700* for the first 1GHz Sonnet upgrade card that came out. And not to mention upgrading a cube? What could be better than keeping a collectors item up to date?

[Carl @ Dec 19th 2005 2:47AM]

Creepy,,, I've started using my 1st Gen 400mhz g4 again like 5 months ago, and decided its time to upgrade its cpu like a week ago... thanks... lol

Definetly will put this to use.

[YourNameHere @ Dec 19th 2005 2:47AM]

If you're taking apart anyway, why didn't you just slap in an intel board and install osx86?

[Mike Cohen @ Dec 19th 2005 2:47AM]

I upgraded my G4/500 "Sawtooth" a few years ago with an OWC Mercury Extreme 1 GHz G4. At the same time I replaced the DVD-RAM drive with a Superdrive & I later replaced the internal drive with a 160G drive and added another 80G drive. It didn't require any firmware updates since I already have 4.2.8 and every OS version including Tiger runs without any patches.

[macsucks @ Dec 19th 2005 2:47AM]

upgrading MACs are oxymoron... why buy a mac if you are into upgrading...

[Erik Stearns @ Dec 19th 2005 2:47AM]

I did this upgrade with a Sonnet Tech 1.0GHz single processor (all the company I work for would pay for). It was similar, but because I already had the firmware updates, it was painless. I was maxing out my processor usage with a 450MHz G4, but after the upgrade, I was only using 30%.

Just a note of caution, the Apple software suite might not be compatible with all processor upgrades (the 1.8GHz models in particular). This is because they come without 2MB L3 cache. I'd like to hear if this is really the case. Does anyone out there have a 1.8GHz upgrade?

[CrimsonMonk @ Dec 19th 2005 2:47AM]

- Bhagiratha
Look at the G5 Service manual they have on this page:

http://www.eserviceinfo.com/service_manual/datasheets_a_1200.html

it'll show you how to strip your G5 to the core, which is what you'll have to do to get to the power supply... Have fun! :)

[blackandblue @ Dec 19th 2005 2:47AM]

being a student i took a more desctructive but cheaper route. Following a guide posted on the appletalk.com.au forum (http://forums.appletalk.com.au/index.php?showtopic=8205&hl=)
i purchased an old g4 400, a clocked QS 933 cpu off ebay, removed the ide port and did it all for under $400AU.
You end up with a 700mhz g4 for about half the going cost. It could be overclocked but i havent tried yet, bit too worried about frying the cpu.
Just something else to consider for the tinkering...

[Dave @ Dec 19th 2005 2:47AM]

Just Upgraded from a dual 450MHz (that I still owe $900 on) to dual 1.8GHz from GigaDesigns for $700 and well worth every penny. Just like the 1.5 GBs of RAM. No need for anymore bottleneck than 100MHz system bus.

The Mactel Machines are gonna rock, and THANK GOD I waited. Forget the G5. In the end, a total waste of our time.

[Adam Grant @ Dec 19th 2005 2:47AM]

Umm...you could have saved yourself a fair chunk of hassle by installing the Classic environment. Tha Sawtooth can actually boot from such an OS9 System Folder as installed under Classic. You just need to Option Boot to get it to come up as an option (or do the cheesy way of setting it as the startup disk in the System Preferences).

[Rich @ Dec 19th 2005 2:47AM]

Mike,

Thanks! I was about to point out the same typo. You beat me to it, and educated me at the same time! I didn't think "payed" was a real word at all...

[critical care @ Dec 19th 2005 2:47AM]

Nice tutorial , but in the end its easier to buy a new mac mini :)

[Mark @ Dec 19th 2005 2:47AM]

I upgraded my G4 733mhz powermac last week to a GigaDesign dual 1.6ghz. Now waiting for my new 250GB drive and pioneer dvd writer. Only problem I have is upgrading the vga card. cant find a decent affordable solution.

http://www.miskan.com/2005/08/dual-16.html

[fabienne @ Dec 19th 2005 2:47AM]

critical care: a mac mini is nice, this machine is designated for multichannel audio requiring internal pci cards.

adam grant: i had none of the original install cds for the machine as i had purchased it on ebay, and wanted to conserve my os x.4 system exactly as it was without too much tweaking (i tend to run a lot of less popular and bleeding edge release unix apps on this machine so many things were already installed from source etc.). if you know of a way of installing classic after the fact on an os x machine, please point the readers in that direction.

aftaab: we purchased through other world computing and had no problems receiving merchandise.

blackandblue: that's awesome. you may want to hang out on hackaday if you have more fun stuff like that.

mvelso: yes and not only are the mirrored door drive revisions not that pretty, many models had interesting manufacturing problems.

tr: the g4 used in this example is not uni n revision 7 and should not work with the particular processor we have. but it does. perhaps you have an idea why? this machine is uni-north revision 3.

cheers,
fabienne

[Laurie @ Dec 19th 2005 2:47AM]

fabienne - having OS X already on the drive won't prevent you from installing or using OS 9.x on the same drive/partition. What's important is that when you formatted the HDD previously (probably when you installed OS X), that you selected the checkbox that said "Install OS 9 Drivers." As long as you did, then you only need to drag a system folder from another working OS 9 install over to your HD, or boot from an OS 9 CD and install it just as you would any other time.

If you neglected to check "Install OS 9 Drivers" the last time you reformatted, then you will have no choice but to add a 2nd drive, as you did, or backup what's on the existing drive, reformat (selecting the drivers this time) and reinstall

[eh @ Dec 19th 2005 2:47AM]

Wait a minute...this is a how-to? A lot of this is common sense. It's just basic upgrading...

[fabienne @ Dec 19th 2005 2:47AM]

laurie: the os 9 drivers checkbox is/was checked. unfortunately, i didn't have a system folder from a working os 9 system. as for booting from the os 9 cd, the 3 official (not copied/pirated/etc) os 9 installer cd's i had on hand would not let me install without completely wiping the entire drive. the smart thing i should have done is partitioned the drive right off the bat when i installed os x. *smile* live and learn.

[Mark @ Dec 19th 2005 2:47AM]

i didnt have OS9 installed, I actually did but had deleted it a week earlier not knowing I needed to have it to upgrade the firmware.

I just booted with an old os9.2 cd I had from my old G3 iBook and installed it without formating or anything. Maybe os9 and 9.1 you had to format but with 9.2 i didnt have any problems.

[Ladyfox @ Dec 19th 2005 2:47AM]

Mark,

As far as a video card upgrade for your G4 there is only really two options; a hacked Radeon 9800 Pro or a hacked Geforce FX 5200. Either one can be found on Ebay for around $85 to $100 and both will have full Core Image support for Tiger. My hubby and I are looking at upping ours to a 1.2 GHz with one of these cards before too much longer. ^__^

[JT @ Dec 19th 2005 2:47AM]

Thanks, engadget. I wouldn't have had the scrote to do this upgrade without your how-to.

I did encounter one problem which you did not: upon reboot into programmer mode, my monitor (Sony HMD-A200) only displayed a blank screen. Apparently, it is incompatible with the video mode my mac had entered.

After swapping in the El Cheapo LCD monitor from the Gateway PC that I usually keep hidden behind the couch, I could see the programmer's screen, and all was well.

By the way, I too have had an OS9 system folder on the thing since I bought it, and booting to that folder allowed me to update firmware without any additional machination.

[dMick @ Dec 19th 2005 2:47AM]

EnGadget ROCKS! Without this tutorial, I would've been lost. I took my 400 MHz PowerMac G4 and bumped it up to 1.6GHz with the PowerLogix 7447 from www.macsales.com for $270

Word of advice to anyone out there, if you get stuck installing OS 9.1 and you "borrowed" it from the internet via torrent download... find another copy. I used an OS 9.0 iMac restore disc on my PowerMac G4, upgraded to 9.1 (free from Apple.com), everything worked fine.

Thanks to Engadget for doing sucn an in depth install documentation and sharing it with us.