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#1 2015-11-30 05:39:47

gsteemso
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From: north of Seattle, USA
Registered: 2015-11-30
Posts: 11
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2003-model PMG5 CPU standoffs

Hi all,

Was pointed at this forum by a wandering bbraun during our monthly Seattle Retro-Computing Society meeting yesterday. Coincidentally, was also given a surplus 2003-model Power Mac G5 (2.0 GHz DP). Haven’t dared power it up yet, and a good thing too! When I opened it up to try and work out (a) what I have and (b) what upgrades to it are feasible, I discovered that some incompetent boob has at some point removed and lost 3/4 of the long screws that hold the CPU/heatsink assemblies onto the motherboard standoffs. Grrr.

Strangely, while some information is available on the web about G5 machines, almost all of it focuses mostly or wholly on the ones with liquid cooling. What little detailed technical information is to be found concerning the air-cooled models is universally and without exception focussed exclusively on the later revisions. Concerning the 2003 editions, the only hard details available come in the form of passing remarks in the discussion of later models — e.g, a detailed description of the weird, complex split standoffs that anchor the CPU assemblies from 2004 onwards mentions that the design is different from the 2003 parts, but doesn’t give any useful details of how.

The two surviving screws are Philips-head with integral lock washers, and they screw into perfectly mundane 1/4" hex standoffs. Is this normal?

Once I get the CPU modules secured properly, I will attempt to boot the machine. Whether the wretched contraption even works or not will determine whether there is any point in further tinkering.

Assuming it boots, the following upgrades are feasible: RAM, drives, AirPort Extreme-G wireless, possibly Bluetooth (though a modernish USB dongle will likely be more capable when the stock card is this obsolete), and MAYBE a faster and/or less inefficient CPU set.

I have seen numerous conflicting reports concerning which G5 CPU modules will work with which motherboards. There seem to have also been a horrifyingly wide array of motherboard part numbers associated with each different model released, which may be a contributing factor. The motherboard label in this thing reads:

• KD349014JQ5DB • 630-4834 630T4831

The CPU modules are labelled:

*KC34702FUQA3B* SG 630-4890 / T4838
*KC347H02DQ9CB * SG 630-4881 / T4838

Those are the top and the bottom modules, respectively. All my research indicates the stock modules use the non-fx PPC970 chips (130nm process, hotter, uses more power). Are these? Can anyone out there tell me, based on this knowledge, whether there are any PPC970fx CPU modules (90 nm process, cooler and more efficient) compatible with this board?

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#2 2015-11-30 13:47:34

TheWhiteFalcon
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Registered: 2015-04-27
Posts: 504

Re: 2003-model PMG5 CPU standoffs

They'd have to be the original 970 CPU's. G5 CPU swaps are super iffy because the bus tends to be keyed to the exact speed and type. The only ones I know that can be swapped are the final Late 2005 models, but even then only the single processor Dual Core models.

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#3 2015-11-30 17:51:53

Schmoburger
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From: Australia
Registered: 2015-04-21
Posts: 281
Website

Re: 2003-model PMG5 CPU standoffs

I know this is probably not a thing anybody really wants to hear, but I would seriously advise against spending any serious money on that machine... the early dual-processor machines had appalling failure rates even when new. The fact that screws are missing would tend to indicate to me that the machine may already have been suffering issues, hence why somebody may have had the CPU's out as part of the troubleshooting process. Many times, people are tempted to try and fix them by throwing parts at them, but he real issue lies in the memory controller chip, leadless solder and various leadless BGA interfaces, compunded by thermal expansion due to the ridiculous amount of heat the earlier G5 processors generated. The nature of the beast is that it isnt a matter of if, but when they are going to become unstable or fail.

But yes, as mentioned above it isnt really worth trying to swap CPU's as they are basically keyed to the logic board... trying to swap and change can have very unpredictable results... you might even end up with it working but having a slower clock speed than you started with (I have read accounts of exactly this occurring). As for the standoffs, what you describe sounds pretty much correct... my old G5, a 2004 2.0DP, from memory had fairly standard standoffs, although from memory, it had recessed-hex screws. I'd have to open it up and have a look to be certain... that machine is now sitting in a junk pile as it became too unstable to even be usable anymore.

My recommendation would be to obtain a later dual-core aircooled model if you fancy a G5 tower, as they addressed the memory controller issue and used a far more efficient and cool running CPU that wreaked less havoc on everything in the vicinity... they are actually as a rule of thumb rather reliable and stable machines. The downside is however, that they do not have much that is interchangable with the more readily available earlier G5's... they use PCIe only instead of PCI-X or PCI and AGP, they use different RAM, different CPU's, even the case has physical differences. But well, for what it's worth, I couldnt complain about my 2.0DC in the slightest.

I know this all makes me look a bit like a negative nancy, but I would hate to see somebody spend a whole motza on upgrading a machine to have it let them down a week later... I nearly did this myself but luckily the machine went flakey before I spent a cent on it.


Stay hungry... Stay foolish.
G5 2.0DC, Yikes G4/500 Sonnet-Enhanced, B+W G3/450, 9600/200MP, 7600/200, iMacs DVSE Graphite and 600 Snow, 7220/200, WGS 7350/180, 6360/160, 5500/250 DE, Pismo, 2x Lombards, 6100/66DOS, 2x CC's, 3x Pluses, 512K, SE/30, SE Superdrive, 2x Classics, IIvx, IIci, IIsi, 3x LC520, 4x LC575, 5x P580, LC, LCIII, //gs LE, 2x ROM 02 //gs', IIe... and I'm outta characters!

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#4 2015-11-30 18:06:05

gsteemso
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From: north of Seattle, USA
Registered: 2015-11-30
Posts: 11
Website

Re: 2003-model PMG5 CPU standoffs

Hm. Not entirely what I had hoped to hear, but sadly consistent with reports seen elsewhere. Oh well, I shall visit the screw wholesaler down the street and drop a dollar on suitable screws. Who knows, maybe it will defy the odds and actually work. Stranger things happen every day.

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#5 2015-11-30 18:09:17

gsteemso
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From: north of Seattle, USA
Registered: 2015-11-30
Posts: 11
Website

Re: 2003-model PMG5 CPU standoffs

Just out of curiosity, has anyone ever tried to redo one of these beasts using good solder? I imagine it would be a very large undertaking, but if I had the time and equipment, I might be tempted to try it purely out of orneriness.

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#6 2015-11-30 18:37:09

Eudimorphodon
Member
Registered: 2014-09-02
Posts: 522

Re: 2003-model PMG5 CPU standoffs

Hey, worse case you can approach this as a metalworking project and mod the case to hold a standard Micro-ATX motherboard. There are some really well done conversions out there...

Or go the other way and install an Apple II board in it. It'd totally rock to see the front panel hacked out to make room for a couple of Disk ][s.


Flap Different.

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#7 2015-11-30 19:13:14

gsteemso
Member
From: north of Seattle, USA
Registered: 2015-11-30
Posts: 11
Website

Re: 2003-model PMG5 CPU standoffs

Heh, it _would_ make a really suitable home for a massively tricked out IIgs setup! Heh. A IIgs driving a 1920x1200 ADC Cinema Display… Possibilities, possibilities!

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#8 2015-11-30 19:18:47

gsteemso
Member
From: north of Seattle, USA
Registered: 2015-11-30
Posts: 11
Website

Re: 2003-model PMG5 CPU standoffs

Speaking of the display, the video card in this beast is a prerelease Radeon 9600. Says “NON-QUALIFICATION SAMPLE” on the part-number label. Considering it also came with a 100bTX Fast Ethernet card in one of the PCI slots, even though the machine supposedly has gigE on the motherboard, I’m increasingly pessimistic about the thing’s life expectancy.

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#9 2015-11-30 21:04:47

ClassicHasClass
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From: Electron Alley
Registered: 2014-05-26
Posts: 1,081
Website

Re: 2003-model PMG5 CPU standoffs

If it's the model I'm thinking of, I don't believe any of the 970FX modules will work in it. As has been pointed out, most of the G5 CPU assemblies were specific to their model.

For my money, the only G5s worth owning are the aircooled 2.3 (DP is more reliable but PC is slightly faster) and the Quad. Everything else is too much trouble, including the iMac G5s, which are just a bag of hurt when they go bad.

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#10 2015-11-30 21:05:21

ClassicHasClass
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From: Electron Alley
Registered: 2014-05-26
Posts: 1,081
Website

Re: 2003-model PMG5 CPU standoffs

s/PC/DC/

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#11 2015-11-30 23:03:40

TheWhiteFalcon
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Registered: 2015-04-27
Posts: 504

Re: 2003-model PMG5 CPU standoffs

The 1.8GHz 2003 DP had like a whopping 47% rate of hardware failures in the first year alone back in the day.

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#12 2015-11-30 23:29:28

bbraun
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Registered: 2014-05-29
Posts: 1,064
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Re: 2003-model PMG5 CPU standoffs

I dunno, I got one of those 2.0GHz dual package air cooled ones (the earlier one) and aside from the CPU singing to me it seems pretty OK.

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#13 2015-11-30 23:35:04

Eudimorphodon
Member
Registered: 2014-09-02
Posts: 522

Re: 2003-model PMG5 CPU standoffs

The 2003 models do have a pretty serious negative reputation. I vaguely recall reading an article examining some claim from Apple that they were fast enough to do (*something*) with HD video in "real time" and they discovered that the systems could only do so if the ambient temperature was in the low 70's; any warmer and they'd start throttling the CPU even with the fans kicked up to full blast. Of course I don't have a link or anything but stories like that were pretty par for the course with those things.

Last edited by Eudimorphodon (2015-11-30 23:39:03)


Flap Different.

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#14 2015-11-30 23:45:32

bbraun
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Registered: 2014-05-29
Posts: 1,064
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Re: 2003-model PMG5 CPU standoffs

I generally turn on the G5's when the ambient temperature is substantially below 70F.  smile
It's a high of 19F today, and my office is between 59F and 62F.

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#15 2015-12-01 21:04:59

cc333
Member
From: North S.F. Bay Area, CA
Registered: 2014-05-23
Posts: 562

Re: 2003-model PMG5 CPU standoffs

My DP G5 (I think it's a 2004 model? It's 2.0 GHz) seems reliable enough. It's just slow.

I did pretty much strip it down and rebuilt it though, so maybe that helped?

c


Main Macs: Early '09 Mac Pro, Mid '12 MacBook Pro 13"
Secondary Macs: Early '08 Mac Pro, Mid '12 MacBook Pro 15"
Playthings: Mac SE/30, 3.0 GHz Mavericks-based HackServe, Many others....
Desired: Lisa, Kanga PowerBook G3, Apple IIc, Apple II, Spare parts, etc.

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#16 2015-12-02 03:57:30

gsteemso
Member
From: north of Seattle, USA
Registered: 2015-11-30
Posts: 11
Website

Re: 2003-model PMG5 CPU standoffs

Seems odd to think of a 2 GHz machine as “slow,” even if it IS 11 years old. Is there something wrong with yours, or are you just mentally comparing it with a modern machine? Any 11-year-old computer is going to come off badly in that comparison.

Your machine is inherently more reliable than one like mine from the 2003 generation that preceded it would be, at least.

Returning to one of the points raised in my original post, I have looked into getting more screws to anchor the CPU/heatsink modules… and learned that they are M3.5 x 10mm with captive external-tooth lock washers. Surprisingly, or perhaps not so much depending on how cynical one’s opinion of Apple is, this is a VERY unusual fastener. M3.5-diameter fasteners are not available at all from most dealers, and when you can find them, absolutely NOBODY stocks ones with captive washers of any sort (such specimens are apparently called “sems”—as in, “pre-asSEMbled”—in fastener-industry jargon).

If you overlook the captive-washer wrinkle, individual-quantity machine screws of the correct dimensions can be found online for as little as 4¢ each if you get the cheaply made ones, but then you have to pay at least $6–7 in shipping for your 1/2-ounce package. This is beginning to seem less than economical given that the machine is only about 40% likely to even boot successfully.

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#17 2015-12-02 05:02:12

cc333
Member
From: North S.F. Bay Area, CA
Registered: 2014-05-23
Posts: 562

Re: 2003-model PMG5 CPU standoffs

Wow! Your post is from 8 minutes in the future!!

I was just comparing it to my Mac Pro (which I'm 100% certain will outperform it in every way conceivable). Unto itself, the DP G5 is quite decent for the most part, but it can't keep up with the modern internet so well, so it was not the most pleasurable experience when I had to do my school homework, for example (the homework site is Flash-based, so it poses quite a problem for PPC Macs, given that the most recent Flash plugin was released 4-6 years ago; As they don't require the latest version, it works, but it's not fast by any means.)

I also have a Quad G5, which I've heard performs very decently, for a G5, but I've never been able to use it due to a faulty LCS (a dreadfully common problem it seems; at least it didn't leak all over the place, because it's the latest revision (from mid-2006), which I *think* is not as prone to leakage). I'm sure it'd run circles around the DP G5 if it were working, though (I just got the LCS repaired, so, assuming I haven't misplaced a million bits and pieces in the meantime, it should finally be operational).

c

Last edited by cc333 (2015-12-02 05:03:57)


Main Macs: Early '09 Mac Pro, Mid '12 MacBook Pro 13"
Secondary Macs: Early '08 Mac Pro, Mid '12 MacBook Pro 15"
Playthings: Mac SE/30, 3.0 GHz Mavericks-based HackServe, Many others....
Desired: Lisa, Kanga PowerBook G3, Apple IIc, Apple II, Spare parts, etc.

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#18 2015-12-02 11:41:33

LCGuy
Administrator
From: Sydney, Australia
Registered: 2014-05-13
Posts: 805

Re: 2003-model PMG5 CPU standoffs

gsteemso wrote:

Seems odd to think of a 2 GHz machine as “slow,” even if it IS 11 years old.

I don't think so...but then again - I have more than my fair share of experience with P4s and Celerys of various speeds around 2 Ghz. I used a G5 1.6 Ghz a few times back when it was new, and compared to the Dell P4/2 Ghz I had at the time it was quicker than a ray of light, though of course comparing my Dell to the G5 was a bit like comparing a Toyota Camry to a Ferrari. These days I own a 2003 G5/2 Ghz DP, and while its still a quick-ish machine, and a rather useful machine (if a bit power-hungry), given that I'm used to newer machines now it doesn't exactly push me back into the seat the way the 1.6 did back in the day.

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#19 2015-12-03 00:41:41

ClassicHasClass
Member
From: Electron Alley
Registered: 2014-05-26
Posts: 1,081
Website

Re: 2003-model PMG5 CPU standoffs

The main problem with the G5 was it was too undercached, IMHO. Look at how much cache IBM crammed into the POWER4 design from which the 970 is descended. Apple in their own tech docs called the G5 "very hungry and very sequential." You really need to keep those pipelines full, and only the last generation with the comparatively generous 1MB L2 per core came anywhere close to doing so. Owing to the G5's design, L3 would probably not have made much difference. If Apple hadn't cheaped out on that I think they would have wrung more out of the core, especially since Motorola wasn't willing to do a whole lot more with the G4 (let alone that abysmally slow front-side bus).

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