20-Year-Old Apple Power Mac G4 Gets M.2 SSD Upgrade, Despite 133 MBps PCI Bus

(Image credit: Journaldulapin.com)

Giving an old system new life by installing more memory or a new storage device is one thing. But plugging a modern solid-state drive into an archaic 20-year-old Power Mac G4 requires a lot of hardware and software hacking, with the end result being questionably useful at best. Because clearly, a modern PCIe NVMe SSD that delivers gigabytes of throughput per second isn't going to deliver its best while running over a PCI bus with 133 MBps of bandwidth.  

Apple originally released its PowerMac G4 in 1999 and then launched its upgraded iterations till 2002. In other words, this desktop is outdated, to put it mildly. In addition to the ancient CPU and GPU, it lacks almost all modern interfaces. So it's nearly impossible to use any modern component with it without complications. But that didn't deter Pierre Dandumont from Journaldulapin.com

So what does Apple's early 2000s Power Mac G4 have to work with in terms of an interface? PCI. Not PCI Express, mind you, but a PCI slot that can be used to install various add-in-cards, such as graphics boards (yes, since the system is based on a Power processor, it lacks AGP as well). Meanwhile, there are PCI-to-PCIe adapter boards that let you install PCIe hardware into PCI slots, though with some caveats. 

Just plugging things in is not enough to make PCIe hardware work with a Power Mac G4. That system for obvious reasons does not support the NVMe protocol used by modern speedy SSDs. But it appears to support the AHCI protocol used by modern hard drives, some PCIe SSDs, and all SATA SSDs. The Power Mac G4 shipped with SCSI or Parallel ATA HDDs, and it looks like Apple used PATA controllers that support AHCI, but we are speculating here. This AHCI support enables the use of PCIe SSDs that use this protocol, such as Samsung's SM951. 

Yet even picking up the right SSD is not enough to make a relatively new drive work in a Power Mac G4 PC that's roughly 20 years old. In a bid to make the drive bootable, a different BIOS (or Open Firmware in this case) is needed and an appropriate version of Mac OS X is required, which Journaldulapin.com explains how to install. 

After all that, there will still be performance limitations, such as the 133 MB/s bandwidth supported by a 32-bit 33 MHz PCI bus (keep in mind that we are talking about a half-duplex interface here), but this is to be expected. 

A legitimate question about installing a new SSD into a system with such a performance-capping interface is whether it would be far easier and faster to just plug in an external SSD using a USB connection. And it is certainly easier to plug in a USB drive, but Apple's Power Mac G4 only features two USB 1.1 ports, which means a 12 Mb/s data rate (1.5 MB/s), an order of magnitude slower compared to what a 32-bit 33 MHz PCI interface provides.

Of course, using a FireWire 400 (around 50 MB/s) connection would have been faster, but connecting a modern SSD over a FireWire interface to a 20-year-old PC would probably have been even trickier than using a PCI slot. 

Then again much, like many of the best Raspberry Pi projects, installing a new component in an outdated Power Mac G4 is a lot less about convenience or improved performance as it is about fun and figuring out what's possible. From that perspective, this endeavor was clearly a success. 

Anton Shilov
Freelance News Writer

Anton Shilov is a Freelance News Writer at Tom’s Hardware US. Over the past couple of decades, he has covered everything from CPUs and GPUs to supercomputers and from modern process technologies and latest fab tools to high-tech industry trends.

  • King_V
    I saw this, and all I could think of is this particular quote from Cave Johnson:
    Science isn't about WHY. It's about WHY NOT??
  • IJustWantToReadOldThreads
    ...such as graphics boards (yes, since the system is based on a Power processor, it lacks AGP as well).

    Uhhh, what? Did the author just completely fail to do the minimal research before writing this article? It's a PowerPC processor, not POWER, and I don't get the implication that it'd prevent AGP. Hell, the later PowerMac G5s did have PCIe. Maybe next time, research before you write...
  • artk2219
    I applaud the effort, but, why not just use a sata ssd with a sata to ide adapter board? It'll still be way faster than 133 mbps, so it will saturate that bus entirely, and it will be generally easier to get up and running.

  • TheScrubofNick
    Only the very first G4 was lacking AGP. All the others had it.
  • Executor32
    artk2219 said:
    I applaud the effort, but, why not just use a sata ssd with a sata to ide adapter board? It'll still be way faster than 133 mbps, and generally easier to get up and running.

    <link snipped>
    Or better yet, use a 2.5" SATA SSD (or for maximum jank, an M.2 SATA SSD with a 2.5" SATA adapter) with a Firewire-capable drive enclosure like this one to get those sweet 400 Mbps transfer speeds.
  • Krotow
    Indeed a project with "why not" moto. Although it have very little use in real life like old 8086 CPUs for NASA satellite repairs in orbit which they hoarded 2 decades ago. But probably is useful for classic computer collectors as failed original drive substitute.
  • Co BIY
    I would like some benchmarks run on this upgrade vs. original setup.

    Great project.
  • Genralkidd
    I'm actually very curious what kind of performance you can expect from a GPU using this method? More specifically I wonder if a traditional PCI bus would even have enough bandwidth for crypto mining. People already use PCIe x1 risers for GPU mining and apparently that's enough for crypto mining, but going down to PCI I'm not sure if that'd be too much of a bottleneck for even crypto mining.