The PowerMac G5 Quad and power usage
Today I performed some raw conversions using Aperture 1.0.1 at a friend’s house, using a PowerMac G5 Quad with 4.5 GB of memory, and a single (non-RAID) drive. The results will become part of the Raw-file Converters article. Without a doubt Aperture has the most attractive user interface (by far) every produced for a raw-file converter (though Adobe Lightroom, still in beta, might become a competitor in that regard).
Aperture on the Quad is notably faster than anything I’ve seen before, roughly 2-3 seconds to convert a raw D2X NEF or 1DsMII CR2 to a 16-bit TIF (no specific timings were done). Compare that to the 7.2 seconds for converting a NEF on a dual 2.5GHz PowerMac using Nikon Capture (see Nikon Capture—Speed and Stability). Aperture does use all 4 CPU cores fully, albeit very briefly, which must contribute to the fast performance. Benchmarks using a large number of the same raw files would be needed to make a precise comparison to other machines and converters, but I have no doubt that Aperture would come out near the top of the heap, if not the very top.
I noticed that Aperture by itself was using about 800MB of real memory (mapped to about 1.2GB of virtual memory). Any test that makes claims about Aperture’s processing speed is worthless unless it verifies there is adequate memory. Otherwise, the test is just benchmarking virtual memory system performance (the disk), and the results are meaningless in any setup that isn’t an exact match (in multiple ways).
Given the massive memory requirements, laptop users shouldn’t even consider Aperture with less than 1.5GB of memory. But even that may not be enough if you want to run Photoshop or other programs at the same time. Plan on getting 2GB for your laptop if you intend to run Aperture.
What a quiet, beautifully-built machine! No PC I’ve ever seen comes close to this combination of low noise and elegant design. It is very difficult to make the Quad break a sweat—nothing we had on hand could blip CPU usage on all 4 cores for more than a moment.
If you’ve put off buying a Quad because an Intel-based version may be coming, wait no longer—the G5 Quad is the first computer I’ve used that makes any normal task appear effortless. But plan on getting at least a 2-drive striped RAID array, because unless you can feed the Quad’s voracious appetite, the 4 cores will be underutilized.
Also, programs that are single-threaded use just one core (equivalent), so the Quad won’t be any faster than a single-core machine for such tasks. Unfortunately, it takes extra coding and testing to make a program “threaded”, and some developers don’t do that work. Still, it’s like having 4 computers in one if you’re running several single-threaded programs at once.
One of my concerns about the PowerMac Quad (until today) was its power usage. The power cable is noticeably larger in diameter than the one for my PowerMac G5 dual 2.5GHz. Its specifications indicate power usage up to 1200 watts—a deal-killer for me in terms of the noise, heat and cost. Try finding a 1200 watt power supply at your local PC superstore—the maximum you’ll see advertised is usually 600 watts. The Quad is apparently liquid-cooled, a nifty feature that costs considerably extra in most PCs.
Knowing that it was unlikely to actually consume 1200 watts, I called Apple business sales, and the sales representative put me on hold to “check with an engineer” on the power usage issue. The answer came back that the Quad uses 1000 watts in a 4GB configuration.
This still made no sense, so I gave an old friend at Apple a call who plugged a Quad into a power meter. His power meter indicated a usage of up to 500 watts while booting, but that settled down to 180 watts at idle. I believe that was with 4GB memory and one hard disk.
Today, I took my Smart-UPS XL 1000VA over to a friend’s house (see Uninterruptible Power Supplies (UPS) for your computer). We plugged in the Quad to the UPS, and its indicator lights showed that at idle the Quad consumes about 160-200 watts, and a bit more at about 100% CPU usage (400% being full use of all 4 cores on the Quad).
In short, the PowerMac G5 Quad, though sporting a massive power supply (presumably for power-hungry PCI-Express cards), actually uses about the same or perhaps even slightly less power than my older PowerMac G5 dual 2.5GHz (with single-core CPUs).
