G4 Power Mac

Three Times the Charm

Again something exciting showed up for my Power Mac G4, the same one I last mentioned in part two of the G4 series. Something that I hoped would do away with a looming reliability issue and give me more options to further expand the machine. What am I talking about you wonder?

For a while I had been looking for period-correct hard disk controller cards from various manufacturers. Recently I was delighted to stumble across a used Acard AEC-6280M that was offered for a very good price one day. Visually in excellent condition but untested. Therefore it was unknown whether it would still work.

What this is about

The AEC-6280 is a PCI-to-IDE controller from ACARD Technologies. It supports dual-channel ATA-133. In the 2000s it offered significant expandability as well as a hefty performance plus over onboard controllers of then common systems in use. The M variant of this card shipped with firmware that allowed a PCI-based Mac to start up both, Mac OS X or the older Mac OS 8 and 9, from storage devices connected to it.

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Since the Power Mac's built-in hard drive interface offers Ultra ATA/33 (ATA-4), Acard's PCI card should – apart from taking over duties from a potentially defective onboard controller – speed up disk access beyond the Mac's original capabilities.

Enough Talk

The expansion card showed no signs of damage so I boldly decided to go ahead and try it with my G4. Installing the card in the lowest PCI slot was straight forward and only took me a minute. Mostly thanks to the Mac's excellent case design. I used Apple's original 80-pin IDE-cable to connect my IDE-to-SD adapter to the Acard's primary IDE channel. It was time to take the upgraded system for a spin finally!

Impact

On first startup the Mac's firmware needed a few extra seconds to detect the bootable drive. After that Mac OS X Tiger did run happily. Even Mac OS 9.2.2 showed up in the Startup Disk preference panel and could be booted into without any hassle. To find out whether or not this upgrade made my Power Mac any faster I decided to run a few benchmarks. As I also wanted to get an idea on how this upgrade would have felt back in the olden days I also threw in a mechanical hard drive, a period correct IBM Deskstar 16GP (DTTA‑351680, Ultra-ATA/33, 16.8GB) which, like the Power Mac G4, had come out in 1999. How would it hold up against the twenty years younger SD-card reader? Here are the results!

As expected accessing the SD-card reader through the Acard expansion card was faster than via the G4's built-in EIDE (ATA-3) port (it is a shame I cannot test the onboard Ultra-ATA/33 port). The mechanical hard drive was the last to cross the finishing line in this race. The following diagrams show in detail how all candidates performed when accessing data sequentially and randomly. Some results might surprise you..

Interestingly a performance gap between the AEC-6280M's two channels was noticeable when running XBench on Mac OS X, putting the second channel up to 15% ahead of its primary sibling in some scenarios. Reading and writing small 4K-blocks made performance dip across all storage devices, controllers and channels. Clearly my old mechanical IBM Deskstar was outperformed by the much more modern SD-card reader – most significantly during random reads and writes. One surprising exception was when smaller 4K blocks were read sequentially – there it was more than half a megabyte faster than its competitor.

ATTO ExpressTools 2.8.2 reported a sustained rate of 25.15 MB/s for read and 22.07 MB/s for write access on Mac OS 9.2.2. MacBench 5's disk test scored 3924 points versus 2562 for the previous setup – which suggests a 53% speed increase.

More benchmark results can be found at the end of this article.

Was it worth it?

Given that the dual-OS startup volume works reliably and at faster speed - heck yes! That alone is a huge achievement. On top of that I now can connect up to four ATA-133 compatible drives to my Macintosh. I am very happy with how this turned out. For everyone who experiences issues with the Power Mac's Ultra ATA port, a dedicated PCI-to-IDE controller card is highly recommended. An ATA-133 variety obviously is not required for the above setup, as measured transfer rates were well below 25 MB/sec most of the time. However, with a faster storage device – like an IDE-SSD for instance – this new card probably will shine. But that's a story for another day.

Detailed Benchmark Results

Further information about the benchmarks can be found below.