Power Mac G5: Cheap Power, Easy Upgrades

Apple did a very nice thing when it introduced the Power Mac G5 in June 2003 – it introduced a line that would use the same upgrade options across the board. Well, until the dual-core models shipped in October 2005, which we will mostly ignore in this article.

External Ports

Power Mac G5

Power Mac G5

The Power Mac G5 was the first Power Mac with built-in USB 2.0 (3 ports), so that was one less add-in card for Power Mac users to buy. It also has FireWire 400 (2 ports) and 800 (1 port), which only the January 2003 Power Mac G4 had.

A nice new feature with the Power Mac G5 was including a USB port and a FireWire 400 port on the front of the machine, along with a headphone jack.

In those days, 56k modems were still a standard feature, and the G5 models used Gigabit ethernet across the board.

In addition to standard 3.5mm input and output jacks, there is also TOSLINK optical input and output.

Expansion Cards

All pre-dual-core models are compatible with PCI expansion cards running at up to 33 MHz on a 64-bit PCI bus. For the entry-level model, that was it. For the more powerful versions, you got two 100 MHz 64-bit PCI-X and one 133 MHz PCI-X expansion slot, which are backward compatible with PCI cards.

AGP Video

All of these machines have an 8x AGP Pro slot for their video card, and all of their video cards included DVI output and most also included Apple’s proprietary ADC (Apple Display Connector), which provided video, monitor power, FireWire, and USB to any Apple ADC display. This means that you can freely swap AGP video cards between pre-PCIe G5 Power Macs.

Hard Drives and SSDs

Every Power Mac G5, including the last generation, has two 3.5″ SATA (Serial ATA) drive bays and a 1.5 Gbps SATA Rev. 1.0 data bus. Most SATA Rev. 2.0 and 3.0 hard drives are backward compatible, and most SATA SSDs are also backward compatible, making a wide range of storage options available for your Power Mac G5. When buying a Rev. 3 drive, be sure to verify compatibility with the Rev. 1.0 data bus, as some Rev. 3 drives do not support the older, slower 1.0 protocol.

The Problem with SSDs

When it comes to SSDs, data is managed differently than on a hard drive. When you write data to a hard drive, it is free to write over any unused sector on the hard drive. There is no need to wipe the old data; the new data simply overwrites it. But SSDs manage data differently, using pages and blocks (sets of pages). When writing data to an SSD, you can write to any unused page, but you cannot write to a used page until it has been erased – and that only happens at the block level.

This process is known as garbage collection (see Garbage Collection and TRIM in SSDs Explained – An SSD Primer for a good overview of this subject), and it is kind of messy. When the operating system attempts to write to an invalid (free but not yet erased) page, the SSD rewrites all of the valid pages in that block to a new block, adds the new data to empty pages in that block, and marks the entire original block for erasure. Garbage collection is the process of zeroing out the block that is no longer being used, which is sometimes handled in the background by the SSD itself. In the best case, the SSD will do all of the zeroing in the background when it is not otherwise busy writing data.

Ideally, the SSD will also manage wear leveling, since no PowerPC version of Mac OS X does so. Mac OS X 10.4 Tiger and 10.5 Leopard don’t support garbage collection, so you will want to find SSDs that automatically do it. Mac OS X 10.7 Lion and later support TRIM, but only for Apple-supplied SSDs. What TRIM does is oversee data writes so that the OS doesn’t try to write to a block that needs to be erased. This helps reduce the number of erase cycles, which are limited for solid state memory, and provides for more efficient data writes and less moving data from one page to another.

A Better Solution

DuraWrite, found in LSI® SandForce® Flash Storage Processors, produces similar benefits to the TRIM command whether or not TRIM is present. And when TRIM is present, DuraWrite creates more free space on the SSD than would be possible otherwise (see Garbage Collection and TRIM in SSDs Explained – An SSD Primer for an overview of this subject). SSDs with SandForce are your best option for the Classic Mac OS, any version of Mac OS X for PowerPC, and quite frankly any version of macOS since then as well.

An additional benefit of SandForce is that it supports RAID, which TRIM does not – not that you are likely to want to use RAID with SSDs on a Power Mac G5 with 1.5 Gbps SATA Rev. 1.0. But if you want to, SandForce will let you. (SandForce began as its own company in 2006, was acquired by LSI in 2012, and has been part of Seagate since 2014.)

First generation SandForce controllers are not fully compliant with the SATA specification and are incompatible with the Intel Haswell processors used in some 2013 and all 2014 Macs. Second generation SandForce controllers have been on the market since late 2010, and this won’t be a problem with PowerPC Macs, which don’t use Intel CPUs.

Memory Simplified

The G3/G4 Mess

Apple used a wide range of memory speeds in the Power Mac G3 and G4 lines:

The Beige Power Mac G3 supports three PC-66 160-pin SDRAM with capacities up to 256 MB for a total of 768 MB. The Blue and White G3 uses PC-100 SDRAM and has four memory slots, as does the Power Mac G4 (PCI Graphics); both support up to 256 MB modules for 1 GB maximum RAM.

The Power Mac G4 (AGP Graphics) uses the same PC-100 modules but supports capacities to 512 MB for a 2 GB maximum, as does the Gigabit Ethernet model. The Power Mac G4 Cube uses the same modules but has only three slots for RAM.

Like the Cube, the Digital Audio model only had three slots for memory (up to 512 MB per stick, 1.5 GB per machine), but the new model moved to PC-133 RAM. The Quicksilver and Quicksilver 2002 used the same modules.

After slowly moving from PC-66 to PC-100 to PC-133 RAM, Apple threw a wrench in the works with the Power Mac G4 (Mirrored Drive Door) – the dual 867 MHz model uses PC-2100 RAM, while the 1.0 and 1.25 GHz models use PC-2700 memory. The FireWire 800 model uses PC-2100 memory in its 1.0 GHz model, PC-2700 in the faster 1.25 and 1.42 GHz machines.

Over the course of the Power Mac G3 and G4, Apple used 5 different speeds of RAM. With the Power Mac G5, Apple greatly simplified things.

Simpler with the Power Mac G5

The 1.6 GHz Power Mac G5 uses the same PC-2700 memory as the fastest G4 Power Macs. All of the other pre-dual-core models use PC-3200 memory, making it easy to mix and match memory modules among machines. Except for the 1.6 GHz model and the Late 2005 models, they all use PC-3200 memory.

But it’s not always as simple as we would like. While most of these models support 8 GB of RAM, four versions are limited to 4 GB:

  • 1.6 GHz Power Mac G5, June 2003
  • Dual 1.8 GHz Power Mac G5, June 2004
  • 1.8 GHz Power Mac G5, Late 2004
  • Dual 2.0 GHz Power Mac G5, Early 2005

For the record, all of the dual-core models use PC-4200 memory and support up to 8 GB of RAM.

Why This Matters

A couple weeks ago I picked up 12 used Power Mac G5s for free, and I already had five at home, including one dual-core machine. One of these has no power supply (I bought a single CPU model for less than a used power supply for my dual processor G5 would have cost me). Some of the newly acquired ones have no RAM, no video cards, and/or no hard drives. But except for the three 1.6 GHz machines and the dual-core model, they all take the same memory. Further, I can readily swap drives and video cards, giving the fastest machines better configurations.

As received, RAM ranges from 512 MB to 6.5 GB. In my book, the fastest machines should have the most RAM, and I now have two 2.7 GHz units, the highest clock speed PowerPC Macs ever built. I will equip both of them with at least 4 GB of RAM, one with a Radeon X800XT video card and the other with a Radeon 9600 with 256 MB of video memory.

I have four 2.0 GHz machines, two are the earlier PowerMac7,2 and the other two PowerMac7,3. Again the newer machines will have more RAM installed than the older ones, probably 2.5 or 3 GB in the PowerMac7,3 and 2 GB in the Power Mac7,2. One 7,3 will have a Radeon 9600, the other a 9600 Pro, and one of the 7,2 machines will also have a 9600 Pro. The other will have one of four GeForce FX5200 video cards.

That takes care of 6 Power Macs. I have two 1.8 GHz duals, which will probably have around 2 GB, and one 1.8 GHz single, which I am guessing will have 1.5 to 2.0 GB of RAM. All of these will have GeForce 5200 cards, leaving me with three 1.6 GHz Power Macs with no video card and no need for RAM or a hard drive. Or, more likely, I will ignore the 1.8 GHz single CPU Power Mac G5 so I can put a GeForce video card in one of the 1.6 GHz models, max it out with 4 GB of RAM and whatever hard drive is available. And the RAM from the 1.8 GHz single can go into a more powerful Mac.

The End Result

After my recent acquisition, I had 16 Power Mac G5s that were not of the Late 2005 family. One of those was a power supply donor, so nothing can be done with it. It’s just a parts machine now, and it looks like two of the 1.6 GHz models will also be used for parts as necessary.

I will have one working 1.6 GHz Power Mac G5 with maximum RAM, GeForce graphics, and an 80 GB hard drive. (I partition each drive, giving one-third of the space to OS X 10.4 Tiger and two-thirds to OS X 10.5 Leopard. This lets me choose between Tiger and the possibility of using Classic Mode and Leopard, which is more modern in several ways.) Two 1.6 GHz machines and the 1.8 GHz single-CPU one will be retired, since I have a shortage of video cards.

I will have two 1.8 GHz dual, four 2.0 GHz dual, and two 2.7 GHz dual Power Mac G5s – far more than I need. Once I have everything configured, I plan to sell the 1.8 GHz duals and two or three of the 2.0 GHz duals (one is set up for Linux), and I will keep both 2.7 GHz models for the time being. I don’t know how much use I will get out of them and may eventually sell one, but for now, I plan to keep them.

I will make my “spares” available locally in the Grand Rapids, Michigan area, since these are large, beastly heavy machines, and I only have two original shipping boxes. I would prefer not to ship if possible, but if you really have your heart set on a Power Mac G5 and are willing to pay to ship it…

I will let everyone know when these are available in our LEM Swap USA group on Facebook. This is a very involved project, but I hope to complete it in the coming week.

For Power Mac G5 Owners

Honestly, for the most part, these sell for a song. You can search Craigslist and Facebook Marketplace and come up with a whole system for under $100. If the price is cheap enough and you already have a Power Mac G5, this could be the least expensive way to max out system memory – or migrate to a whole new machine simply by moving your hard drive to your acquisition.

There’s a lot of power for the money in these, especially the dual-processor and dual-core models. Whether it’s for image work, design projects, writing, and gaming, there’s a lot of life in these old aluminum enclosures. Just be sure to add a copy of TenFourFox for relatively modern browsing on the Internet.

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