Yet Another G5 Roundup

Lawrence Person writes "This article on Low End Mac talks about why the PowerPC 970 is so fast, covering its superiority to Intel chips in Multiply Accumulate, double precision arithmetic, and Fast Fourier Transforms, among other operations. A short, clear article for those who don't have the time to wade through Parts 1 and 2 of Ars Technica's exceptionally detailed dissection of the 970/G5." Trollaxor writes "IBM has a neat two-page history of the PowerPC architecture, detailing its evolution from the first RS/6000 chipsets in 1990, through the POWER ISA, and into the processors that we know and use today. A very interesting read."

Comments

Yea, but does it run Linux?

[Znonymous Coward]

Seriously. The G5 PowerMac has like 9 fans in it that are controlled by the OS (Mac OS X). It will be easy to run Linux on it, but will Linux properly control the fans to keep the system from burning up or flying off the desk?

Re:Yea, but does it run Linux?

[Duke Thomas]

I never thought of that. Why did Apple put the OS itself in charge of regulating the temperature? Why couldn't the fans be controlled by some simple thermostat like mechanism quite apart from the operating system? Apple has been big on software controlling hardware for a while now, but this seems a bit much.

Re:Yea, but does it run Linux?

[gerbache]

If a fan fails, it's not necessarily going to kill the computer. Considering Apple says they used 9 fans to reduce noise, something tells me that the failure of a fan will not be a catastrophic failure in terms of the entire system. If the OS is controlling the speed of the fans, then the OS should be able to be written to either limit speeds or shut down the system upon the failure of a fan, so it shouldn't be a real issue. I really don't see why so many people are all hung up on the fact that it uses 9 fans..that's not too many more than my PC desktop uses if you count all of 'em.

Re:Yea, but does it run Linux?

[MrTangent]

There are actually two hard drive bays. Look closely.

The lack of more than two hard drive bays was a concern of mine as well, but the drive that ships with the G5's is 60 to 250 gigabyte Serial ATA. Factor in the plethora of fast Firewire/Firewire 800 external drives and most Mac users will be as happy as pigs in shit (as well as Fibre channel XServe Raid for multi-terabyte storage for the higher end users). So you can get half a terabyte internal Serial ATA in the G5's if you chose to pay the premium. I think that's more than enough for 99% of the population.

I do agree there's some aspects of the G5 design that seem like a step backwards over the previous G3 & G4 'El Capitan' case. While two hard drive spaces is fine for most users, the G4 allowed you to have four internal hard drives. The lack of a second optical drive bay is also a "step backwards" over the G4 design (this can be rectified with an external Firewire drive if needed, and again, most users don't require a second optical drive).

For me though the biggest gripe I have with the G5 case is the removal of the drop-down motherboard door design on the G3 (Blue and White) and G4. The one button access with drop-down door was an amazing feat of engineering and it saddens me to see this go. The new G5's internals are very elegant but installing and upgrading RAM, PCI and AGP cards is so much easier on the previous G4 and G3 models (although the G5 certainly looks easier to upgrade/get into than most PC boxes I've worked on before).

As far as the fans go, I have no gripe there. While it might be more moving parts, the idea of thermal zones is a sound idea and will help keep the machine cool and output less decibels. By the way, the fans will be replaceable. You make it sound like the machine will be junk just because one fan fails. I'm sure Apple has thought of this and will provide replacement fans.

One could also argue that by having nine fans that work in tandem you'll have less chance for failure since no one fan will be running at 100% at all times like on other machines. This quote kind of explains what I mean:

"the candle that burns twice as bright burns half as long."

Re:Yea, but does it run Linux?

[pmz]

I've used PCs now for decades, have Amigas and Sinclair QLs and, goddamnit, Dragon 32s still in working order, but I don't have a SINGLE fricking machine that relies upon a fan working that's more than three years old.

For PCs, this may be true, but for better hardware, such as (hopefully) the PowerMac G5, the fans should last at least five years, not three. This has been my experience with Sun workstations, where the ball-bearing case fans begin crapping out after five years of 24/7 operation (five years powered-on, not five years OS uptime, of course).

Re:Yea, but does it run Linux?

[King Babar]

There are two things (yeah, just two) I'm not 100% happy about on the G5 series:

1. The relative lack of expandability (there are only two drive bays, for example, and both are already in used by default - one HD, one optical media)
2. NINE FANS! Holy crap Apple, what the HELL were you thinking?!

OK, so others have pointed out that you get two hard drive bays, and the SuperDrive is standard, making that a bit less of an issue in my mind.

About the 9 fans, if they turn out to do a better job of managing heat than the 747-style fans in the dual-G4 I've got on my desk, they could put 15 fans in there and I'd still be thrilled. Seriously, the G4 case is splendid, but the cooling system on the latest dual processor models...somebody should have been shot for it to be this loud. (Okay, I'm fine now...)

Another point about the apparent smallish number of hard drive bays is that I think this makes sense because we have crossed an important threshold:

From now on, you'll want a disk or two at most on a desktop. If you need more storage, drink the kool-aid and get yourself a proper RAID.

Honestly, the two disks the G5 will hold can bring you up to half a terabyte. Anymore than this, and arguably even *this* much, and what you really want is either a big old server in a closet somewhere or a RAID appliance of some kind. If you want to use the G5 itself as a server, as luck would have it, Apple also announced a nifty fibre channel PCI card that lets you attach the XRAID among other amusing devices.

*My* only objection to the G5 machines is that I don't have one. (sniff)

Re:Yea, but does it run Linux?

[phillymjs]

The relative lack of expandability (there are only two drive bays, for example, and both are already in used by default - one HD, one optical media)

Wrong. You get one optical, but there are two bays for SATA hard drives. So you have one unused bay. What I don't like is that there is no ATA backwards-compatibility, so it looks like I'll be buying an external FireWire case for the hard drive in my G4 now, if I want to keep it. I don't think you have the option of adding an ATA PCI card, either, because you'd have a tough time running the cable to the drive bay without interfering with the cooling zone setup.

NINE FANS! Holy crap Apple, what the HELL were you thinking?! I mean, nine fans. That's NINE moving parts. And if any of them fail, presumably that's the end of a $3,000 computer.

I'll tell you what they were thinking: Nine fans spinning slowly and quietly move as much air as the two or three fast-spinning, deafening fans in the average PC these days.

Also, your $3000 G5 will be much better designed than the average PC. Have you seen the clear insert in behind the removable side panel that divides the cooling zones? That's not there just to look cool, it is there to properly duct the airflow to where it is needed in the mcahine. I read in one article that the computer will not even power on if THAT is not in its proper place-- so I'm feeling rather certain that Apple has taken fan failure into account, and if necessary you'll either get a warning and have a minute to do a graceful shutdown manually, or the computer will promptly, gracefully (or not) shut down on its own.

~Philly

Ah yes, the early days!

[dbirchall]

In April of 1990, I was visiting a friend at Utah State University in Logan, UT. The IBM rep (nice lady) came around to the computer center (which was nice of her) to try to sell everyone PS/2's - or at least PS/1's (which was less nice of her).

But she brought this one thing with her that looked kind of like an overgrown PS/2, and had a goshawfulbig monitor hooked to it... and was running UNIX. Being a geek even back then, I noticed this and asked what it was and if I could play with it.

'Twas some very early RS/6000 model, quite unstable at that point in time, OS-wise. I have no idea why she was allowed to bring it on campus. Maybe she was trying to convince them to move away from their Ultrix vaxen.

By IBM's timeline, that would have been a POWER (no numbers after it) chip, predating the PowerPC by a chunk of time. I never stopped to think about it before, though.

Multiply and add

[Matthias Wiesmann]

One thing that irks me in the low-end mac article is that it states that the G5 can do a multiply add in one cycle. While this is true, this is nothing special about the G5, the multiply and add instruction has been in the PowerPC instruction set since the start - my Powermac 7100 (technically à G1) already could do this. This is in fact pointed out in the intersting article by IBM about PowerPC.

I just think it's pointless until

[BoomerSooner]

they get a damn OS that is built specifically for a 64bit processor instead of a 32bit patched. It's kind of like running DOS on a Pentium, pointless.

Re:I just think it's pointless until

[dhovis]

Actually, that isn't really true. Because of the way the PPC ISA is set up, there isn't much advantage to switching the whole OS to pure 64 bit. The main boost you are going to see here is the ability to use more than 4GB memory, and you can implement that on the G5 with just a recompile.

Individual apps can be switched to 64-bit and operate in 64-bit mode if needed, even if the OS doesn't use 64-bit mode itself, so long as the OS supports 64-bit addressing

Unless you need to do 64bit integer math, your app will see no benefit from switching to pure 64-bit. In fact, your app may slow down and waste memory. But an app can still take advantage of the main benefit of more addressible memory whilest staying (essentially) a 32-bit app. This is thanks to the fact that PPC is a 64-bit architecture with a 32-bit subset.

There are still optimizations that need to be done to improve the compilers for the G5, but very few of those optimizations have anything to do with being able to do 64-bit integer math.

whether the figures being offered are reliable

[dpilot]

And of course they're being compared with P4 numbers that are now "mainstream." But when the P4 was first introduced, it was "peaky" and irregular, behaving much different from the well-understood PIII and K7 cores. AFAIK, aside from speed bumps, both internal and frontside, and cache size increases, it's still essentially the same "net-burst" core that received such mixed reviews on introduction. Oh, and quite a bit of compiler work, I'll guess, not to mention the new SysEnter stuff under Linux.

Intel got much-deserved heat on the P4 introduction, though that seems forgotten now. IMHO the early irregular performance seems to have been handled by tweaking compilers and ramping speed until the valleys are mountain glens. For that matter, Merced seems largely forgotten with McKinley and Madison. Adoption has simply happened over time, because it's Intel.

But there seems to be an air about that everyone else's (PPC970, K8) difficult launch is nearly fatal, and we should wait to adopt until these issues are ironed out. Of course many of them are volume-related and won't be fixed by anything but production and experience, same as P4 and I2.

We seem to be a bunch of monopoly-making sheep, more times than just this one.

Re:FFT is a good mesure

[torpor]

It need no be said that this is good for my industry too.