Memory
After opening the case and removing the fans (described above), it's simple to add RAM. The RAM system is a dual-channel setup, so RAM works best when added in pairs, and it must be added in matched slots (the same slot in each bank). Even then, I had trouble with the stock Apple RAM in the first two slots and my 1gb of third-party (G5 certified) RAM in the second slots -- I had two kernel panics in the first ten minutes! I then tried switching the Apple and third-party RAM so that my 512mb modules came in the first two slots. While that seemed to work, About this Mac told me the machine only had 1gb of total RAM, instead of the 1.5gb that should be there. So I purchased a pair of replacement 512mb modules, and they seem to be working fine (the first 1gb is going back to the place I ordered it from). The kernel panics related to the bad RAM are still the only issues I've had with this machine since it was new.
Noise
Much has been written about the G5's collection of fans and their ability to keep the noise level low on the new machine. For the most part, this is very true -- the G5, in day to day use, is notably quieter than the G4 next to it (and way way way quieter than my homebuilt Linux machine). Even after all the CPU-stressing benchmarking I did, and hours of playing the latest 3D-based games, I never heard the fans ratchet up to anything louder than the G4. These fans move a lot of air at relatively low speeds; you can easily feel the wind being sucked in through the multitude of holes in the case. This helps keep things cool and quiet.
There are two situations, though, where you get to hear the G5 at full roar. When you boot in single-user mode, or into FireWire target disk mode, the fan management system (which regulates the fans' speeds to keep temperatures within check) isn't available. In those cases, the G5 then goes into its "safe" mode, which means to run the fans at full speed.
And at full speed, the Dual G5 can suck in a lot of air and turn it into a lot of noise. How much air does it suck in? Check out the image to the left; yes, that's a piece of paper stuck to the front of the G5 due to the strength of the fans running at full bore! You can't do this in normal operation as there's not enough wind pressure -- the paper just drops to the floor. Clearly, sticking a piece of paper to the air intake on your G5 is not recommended as a general practice; I had a helper and the paper was on the front of the unit for about one second.
While the fans are blowing at full steam, there's a ton of air being pushed through the case. I was afraid we wouldn't see our cat again when he walked by the front of the unit during the test! My calendar, pinned to the wall, looked as though it was being attacked by an angry poltergeist, flopping around up and down and side to side. So yes, these fans really can move a lot of air, and they can do so in a hurry!
And how loud is it? I made a recording of my G4/733s normal noise level, the G5 in normal operation, and the G5 in "full vacuum cleaner" mode. So take a listen for yourself (headphones are recommended to hear the subtle differences between the first two; you won't need them for the third!).
Overall, Apple's engineers did an amazing job with the noise management on the G5. Yes, I can tell it's on, but it's quieter than my G4 at all times, even after running some intense 3D games for an hour or so. I'm going to run an extended test at some time to see what it takes to get the fans humming, but for now, they seem to stay quiet during my normal usage pattern, which includes some relatively intense use of the 3D graphics card.
Further update on the noise: Now that the machine is back in my computer room, it's apparent how quiet the box really is. I have the G5 on one side of the desk, and the G4 (until I finish transferring stuff; I'm waiting on Panther's release) on the other, and the G4 is clearly the louder machine. That's not to say the G5 is silent, as I do hear occasional noises from the box - the hard drive, sometimes the high-pitched whine, and very occasionally I hear the fans kick it up a notch or two, though I've yet to hear them go into full blower mode.
Design
In addition to the great work inside the case, the outside of the G5 also has some niceties. The latch that allows you to open the side panel includes a mechanism for a lock, and the ports on the back are all nicely laid out and clearly labeled. The power plug fits particularly nicely in a shaped receptacle. The user's manual, which I know none of us read, is actually relatively thick and informative, with great graphics. Finally, and I do mean finally, it's great to have a FireWire and USB port (along with headphone input) right there on the front of the machine.
While I originally disliked the "cheese grater" design when I saw it on the web, the machine is much more elegant in person, and it is larger than the previous generation G4s. Excluding the handles at the top and the bottom, however, it's really not that much bigger. My G4/733 measures 17" in height by roughly 9" in width, allowing for the slight bulge in each side. The G5 is 20" tall with the handles, which add approximately 3" to the overall height. The G5 is actually narrower at 8" in total width. The exterior of the case stays cool to the touch at all times, though it is a bit warm in the back near the rear air vents.
Dislikes
Overall, I'm very pleased with the box. There are some concessions due to the design, however. The first is that there's only one externally accessible drive bay, so you can't put an internal CD-R in below the factory unit. The second limitation has to do with internal drive space -- there's only room for one additional internal drive. However, with FireWire 800 ports available, it's not much of a problem to plug in an external drive instead.
As mentioned on other sites, there are some odd noises from the G5. There's a high-pitched whine that I hear occasionally when doing things, and the hard drive is audible (ironically, due to the lower overall volume of the other system noise) when in use. However, both of these noises are transient and quite quiet, and in my computer room (with two PCs and a Linux box), I have to listen hard to hear them.
Finally, there are some considerations with compatibility with the G5 chip. VirtualPC, which I don't use, won't run at all and will require a fairly healthy rewrite in order to function. Many other programs will have to be updated to take full advantage of all the power offered by the G5 chip, but that doesn't mean they run slowly in their current state.
Performance - How's it Feel?
As with each new generation of PowerMac, this machine is clearly faster than its predecessors. Unlike previous revisions, however, the G5s represent a huge step up the performance curve. As you'll see in the benchmarks, the Dual G5 is a very fast machine. Subjectively, it also feels fast. Windows resize quickly, long lists scroll rapidly, iTunes visuals on a nearly full-size 1280x1024 window run in excess of 35 frames per second, and in-game performance is stellar, as the benchmarks will show. But the best news of all is that it actually feels fast. Click the mouse, and stuff happens, and happens quickly.
I ran a couple of unofficial tests (not included in the benchmark sections) that demonstrate this huge performance leap quite clearly. First, I used iTunes to rip a CD (12 songs, 43 minutes) on both the G4 and the G5. On both machines, I set iTunes to rip into MP3 format at 192kbps with VBR set to high, and songs not playing during import. On the G4, it took 7 minutes 48 seconds, with a maximum observed 8.5x rip speed. On the G5, it took 3 minutes and 43 seconds, peaking at 16.4x speeds.
As noted in the feedback thread on our forum site, the limiting factor in this test is the speed of the CD-R. That was by design, as I was trying to get a sense for the improvement in ripping speed from one machine to the next, with all factors in play. But to provide a sense for just how fast the CPUs are, without the CD as the limiting factor, I just repeated this test after copying the same CD (12 songs, 440.5mb) to the hard drive. I then used Advanced -> Convert to MP3 (with the same settings as above) and timed the conversion process. On the Dual G5, it took 1 minute 3 seconds (about 7MB per second!) to convert all 12 songs. On the G4, the total time was 4 minutes 19 seconds (1.7MB per second).
Note that this does not mean that the fastest way to rip songs to your collection is to first copy them to your hard drive. Since the CD is the limiting factor in the "rip straight from CD" method, it will take just as long to copy the songs to your drive as it would to both copy and rip them into iTunes. But this is a much better way of showing the speed differences between the G4/733 and the Dual G5/2.0Ghz CPUs.
Second, I installed Marine Aquarium 2.0 and used its "Display Frame Rate" option to compare the two machines. Because of differences in monitors, I wasn't able to run identical resolutions on both boxes, but the results are still clear. On the G4, with a 1280x768 resolution, I saw a consistent 167 frames per second. Moving over to the G5, at 1280x1024, the frame rate was in excess of 440fps. In short, this is a fast machine, and it's by far the most responsive Mac I've ever used in OS X.
Finally, I took a screen movie (using an upcoming release of Snapz Pro X) at 1280x1024 (scaled to 960x768) of the machine opening 10 applications in about 10 seconds. This wasn't any 10 apps, though -- the list included both iMovie and iPhoto, complete with its 2,500 image library. Click here, or on the image below to open the 1.8mb movie in a new window -- you'll see some artifacts due to the compression and the scaling of the screen, but this is otherwise untouched.
In total, it took about 10 seconds to open those 10 applications, and that includes a bit of lag due to the overhead of capturing the movie while launching the programs.
Conclusion
In case it's not obvious, I like this machine a lot. It's not perfect, but it clearly represents a new generation of computing on the Mac. Back when OS X first came out, I was involved in a number of spirited debates with people about its performance on then relatively new hardware (G3/500s, Beige machines). My position then was that OS X wasn't designed for older machines, or even current machines, but rather that it was designed for the machines of the future, given that Apple clearly had a long life expectancy for OS X (they got 20+ years out of its predecessor). With the arrival of the G5s, I believe those machines of the future are now here...
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