# Activity Monitor Suddenly shows ONE CPU in a dual 2.0 G5- HUH??????



## Windsong (Oct 9, 2009)

I bought a dual 2.0Ghz G5 about a month ago. It worked fine til today. I went away for 30 minutes & found the machine frozen with the main fans running full blast.
The machine was frozen with a panic.

Two restarts resulted in freezes. The third time it booted.
I checked the startup drive from the utility. It showed ok.
Third Restart.. kernal panic.

I wanted to see what was going on so I opened the activity monitor.
Where it *normally shows two "frames"* representing the two processors activity, 
*Now only ONE CPU "frame" shows. *
*Did one of my processors just die?*
Is it even possible for a dual G5 to run in such a state?

I finally restarted & I'm using the computer right now. Still shows only one processor. 
I'm attaching the panic log, if anyone can decipher what it means.

*How can I tell if what I didn't think was possible... IS possible?*
i.e. a dual 2.0 actually runs on only one of the CPU's?
Also, 
*Will running in this state until I can replace the CPU damage the computer??*

And if *ALL* the above is true....
**IMPORTANT** 
*How close a match does a replacement CPU (ebay etc) have to be?*

For instance, on ebay I just found a single G5 2.0 (from a dual 2.0 system, and the description says this:
"2GHz Apple Power Mac G5 CPU Processor 630-4890 / T4838"

*Where* do I find the numbers on my system to match the above?? 
Are these the actual processor model numbers, motherboard numbers and/or the computer model numbers?

I don't even know how to open the G5 processor/heat-sink "cover" to get a look. I don't want to tear off the wrong thing, but I can't see obvious way to get at the CPUs.

I need Help here. I've never encountered anything like this.

I just check the profiler and this is what it shows...

Hardware Overview:

Model Name: Power Mac G5
Model Identifier: PowerMac7,3
Processor Name: PowerPC G5 (2.2)
Processor Speed: 2 GHz
*Number Of CPUs: 1*
L2 Cache (per CPU): 512 KB
Memory: 4.5 GB
Bus Speed: 1 GHz
Boot ROM Version: 5.1.8f7
Serial Number (system): G85012Z6QPR
Hardware UUID: 00000000-0000-1000-8000-001124315BCE

It SAYS I have one CPU. 
Temp sensor shows CPU A Die Temperature 134º F
CPU B Die Temperature _"This sensor is no longer connected"_

HELP?


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## ElDiabloConCaca (Oct 9, 2009)

Yes, it is possible for a CPU to die.

Yes, it is possible for the computer to continue to run on the one, remaining processor.

Yes, I think this is exactly what happened to your computer.  It may be that a processor is incorrectly seated in its socket, as well.  If you're experienced enough and know what you're doing, you may want to remove and clean the processors and the sockets -- otherwise, a trip to a repair center may be in order.


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## Windsong (Oct 9, 2009)

Thanks "ElDiab",
What concerns me then, is the fact that the fans (or *one* of the rear case fans) case fans spins up (approx 25% faster) for 4 seconds then drops to "normal", more often. I never noticed the fans spinning up much at all before, unless under heavy load.

Maybe I just answered my own question. The computer seems to labor a bit, as if it searches for processor B by default... then shifts the load back to "Processor A".
I guess that'd make sense. It's trying to do _*double duty*_.

So we're back to the question buried in the middle of my original post. 
*Which family (or series) of processors do I need to choose from?*
In the example above (the ebay auction), the seller seems to be denoting a family possibly and maybe a motherboard model. Hard to tell until I open it up and look for similar numbers on my machine.

Do we have any deep thinkers out there who know what range or variance *(if any)*, is allowed in replacing only one of two processors?
Also, are they the same, or are they "mirrors" i.e. "Processor A" *MUST* be replaced by a "Processor A". Am I making sense?

I'm guessing that it must be pretty close to "a mate" for the remaining processor. But are they two of the same, or reversed (mirrored) in design?

Which leads to the next question....
What if I see an auction for a set of TWO? 

Would that give me greater leeway in the selection of compatible models.??
i.e I have a MDD dual 1.25 (firewire 400) with a fried processor.
I've learned that since both processors sit on the same board, and the designs didn't change that much, I have more leeway (as long as it's a firewire 400). 

Am I right in suspecting that with all the changes in the G5 line, I need to stuck much more closely to the "identical" numbers, as in the auction above, or can I replace both with a set from say....
A late 2004 model? 
...A 2005 model? ..(mine is a June 2004 model w/PCI-X slots).

*What is the LIMIT of compatible processors?*

*That's the "new" big question. *
*
...compatibility. *

Where might I find a chart, *(or does someone know)* which numbers (i.e. "630-4890") or "T4838" (from the auction listed in my 1st post) *need* to match??.... 
Tom


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## ElDiabloConCaca (Oct 9, 2009)

Dual-processor machines must have two IDENTICAL processors (in terms of speed, bus speed, etc.) installed in order to function properly.  You cannot install a 2.2GHz processor and a 2.0GHz processor and expect it to work -- they must be identical in ALL respects.

If it were me, I would choose to purchase the EXACT processors that originally shipped with the machine.  In the new Mac Pro towers, there are many success stories about swapping the original Xeons with newer, faster Xeons -- as for the G5s though, I'm not sure what the compatibility "buffer" would be.  I would err on the safe side and use the same, exact processor that shipped with the machine.

I do not have a G5 to tinker with, so I'm not sure about model numbers or anything.  This is just about as far as I am able to go with this query, unfortunately.  Perhaps someone with more G5 experience can pick up where I left off.


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## djackmac (Oct 9, 2009)

I'd try to reseat and then recalibrate the processors before going off and purchasing a new set of processors. These processors can be known to come loose over time with the natural vibrations of use and I've fixed a few of them by just reseating the processors. The heat sink cover is locked on by a plastic rivit of sorts you must artfully dig out with an exacto knife and a wood screw before removing the heat sink cover. Then if you wiggle the cover the right way it will come off but at this point it is easily bent. After that is done just remove the processor fan assy then you can remove the processors. You will need a T-handled 2.5mm hex driver to loosen the processor standoff screws (4 each processor). After this you can reseat the procesors and test. If you are lucky this will fix it without having to recalibrate, because as far as I know only Apple shops have access to the Apple Service Diagnostic for recalibrating the processors. But if you decide to buy and replace the processors on your own you will still have to have the processors calibrated by an Apple certified shop unless you don't mind your fans running full bore whenever the machine is on.


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## Windsong (Oct 9, 2009)

Thanks Dj,
I've been pulling every which way. There seems to be a rivet at the top of the G5 heat sink cover attached to the bottom plate that separates the PCI cards. Also, at the bottom of the heat sink cover there appear to be two pins going down into the "base plate" of the machine.

I'm not sure where you're telling me to look (top, side, bottom? of cover), and what the exacto knife & wood screw (????) are for. 
Can you be a teeny bit more specific?
Great thanks,
Tom


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## djackmac (Oct 9, 2009)

Windsong said:


> Thanks Dj,
> I've been pulling every which way. There seems to be a rivet at the top of the G5 heat sink cover attached to the bottom plate that separates the PCI cards. Also, at the bottom of the heat sink cover there appear to be two pins going down into the "base plate" of the machine.
> 
> I'm not sure where you're telling me to look (top, side, bottom? of cover), and what the exacto knife & wood screw (????) are for.
> ...



The rivet is though the top of the heatsink cover and through the top separator plate. You have to cut around the inside of the plastic in a circular motion to remove the rivet itself. Once the rivit is out you screw in the wood screw into the hole the rivet came out of to pull out the rest of the plastic insert that the rivet was inserted into. Then you slide the cover backwards towards the fan and pull up to work the cover out. The "two pins" you refer to are just for the tabs that are a part of the heatsink cover to catch. Its really a huge pain to remove that plastic rivet if its your first time doing it. I've done several so it just takes me a minute. I wish I could explain better than I have but I really can't.


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## Windsong (Oct 9, 2009)

Ummm, 
WOW...
I figured out "the rivet thing" in the interim while you posted the above. I hadn't seen that teeny tiny gray thing...
It's exactly like the push rivets that are used in cars to hold on the interior panels... pull the "male" rivet which was splaying out the "female" pin.
*Were these people on crack when they designed this?*

I thought my MDD was a pain to work on. 
All you have to do there is deal with difficult cable routings... *sheesh!* 

Also, on the subject of crack, I assume the design of the teeny hex fasteners down the center of the heat sink processor assembly was also done on "_chemicals_"    

They've made it practically impossible for anyone but a service tech with special tools to......
...Oh, I get it.. Stevie wanted no more "system mods"...

So I got everything off and out, blew out dust and reseated the processors. 
Re-assembled, and now I get a startup chime *but absolutely no video,* and though I hear the hard drive working like the Dickens, I get no startup screen, no video output, which I *was* getting before I did the takeapart. 

What's odd is, the fans seem to be running in dual mode, at least as it tries to startup. 
The first time after reassembly, I had to do a hard shutdown because of startup chime, but no starup.... 
And when I pressed the power button next, 
*I got a single tone... about 1.5 seconds. *
The next attempt I got the regular chime, but still no real startup.

I forgot to ask. 
When you pull and re-seat the processors *do you need to do something akin to resetting the PMU in a G4?*

Totally forgot to ask.

I assume the system must be somewhat confused when the processors are both pulled and re-installed. 
Seems odd that now I don't have at least what I had *BEFORE* I did all the surgery...

The video card is brand new. I pulled and reseated it as well, since I hear the machine and drives trying to do 
*a whole lot of something* on power button press.

But after 40 seconds to a minute, it just seems to hang there.
This is *not* a "freeze"... just powerlight glowing & no video.. 

Every minute or so, I hear some more disk activity but no startup screen.  
I did do a "control option RP" (I let it "chime cycle" three times) assuming it wouldn't be a bad thing. 
*
But the G5 is a new animal to me.*

*So now.. 
IS there something on the motherboard that might need re-setting, after re-seating the processors?*

You thoughts??
*And* with great thanks for following me this far  ::love::
Tom


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## djackmac (Oct 9, 2009)

Sometimes it takes a few tries to seat the processors correctly. If you've tried 4-5 times and its still acting up, try running one processor at a time in the top spot. It may help rule out which processor is bad. Even if its not calibrated the worse thing that will happen is the fans will stay full bore but it will still POST and boot properly. But this is subjective because some Power Mac G5 dual processors won't run with just one processor, but if it is one of the ones that won't run on one processor it won't power on at all.


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## Windsong (Oct 10, 2009)

Thanks *once again* DJ,

I'm off tomorrow (today) to get 3 & 4 mm hex drivers. I had to "make do" today, and not realizing that the hex screws *aren't *meant to be removed, I was terrified that I'd lose one in the abyss. eek! 

I got a pdf repair manual today, but it didn't arrive until after "surgery".
Also going to re-clean under the processors. I fear I may have moved some dirt around in the process of blowing with canned air etc.

Do I absolutely need to reassemble everything before a quick test?
The manual says the hex hold-downs are mandatory, and I will do that.
But if I'm going to try a few times do you think it's ok to leave the heat sink cover off, just to test startup? 

Also, do you think it's unwise to lightly clean the contacts?
I have some high end pro synthetic cleaning swabs used for video heads (no lint) and pro contact cleaner (no residue... way better than 91% alcohol).

There was no smell when processor B stopped processing.
When my MDD 1.25 dual fried, you could smell it easily.
Just trying to think positive (ly)   ::angel::


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## ElDiabloConCaca (Oct 10, 2009)

I don't think it's ever a good idea to run a CPU without a heat-sink for more than, say, 1/2 a second or so.  Especially a hot and power-hungry processor like the G5.  If there isn't any damage to the processors now, running them without a heat-sink will surely get you some damage in a jiffy.


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## djackmac (Oct 10, 2009)

Windsong said:


> Thanks *once again* DJ,
> 
> I'm off tomorrow (today) to get 3 & 4 mm hex drivers. I had to "make do" today, and not realizing that the hex screws *aren't *meant to be removed, I was terrified that I'd lose one in the abyss. eek!
> 
> ...



Make sure you get a 2.5mm hex driver. I've never found a G5 that hasn't required a 2.5mm driver yet. You can leave the aluminum heatsink cover off permanently if you want. Its only feature is to hide the processor heatsinks. The fans will always blow high without the clear plastic shield on. Their is actually a magnet on one of the shields tabs to bring the fans down to normal when putting the shield back in. But if the fans still stay on high with the shield in and the machine otherwise works properly, that is a way of telling you it needs recalibrated without having the Apple Service Diag to tell you that. Clean the contacts as you see fit, but if there is not any visual indications that they need to be touched I stay with canned air, because if a few of those pins get bent/broken off, you'll need a new logic board.


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## Windsong (Oct 10, 2009)

> I don't think it's ever a good idea to run a CPU without a heat-sink


No, I wouldn't do that. In fact the processor board is screwed onto the heatsink as a unit from underneath (as opposed to the MDD where the heatsink lifts off to expose the bare top of the processor, which you then lift off the motherboard. 
And OK I'll get a 2.5mm as well. My tool kit is a jumbled messm, so I don't know which size I actually used, just tried different sized until one fit.

I'm guessing (from 1st hand experience), the problems with that single contact point were attempted to be designed out of the G5 system. From looking at the attached picture you can see they reversed the attachment. The processor board itself is screwed onto the heatsink from *underneath*. 
You can easily disassemble the component to examine replace the processor board, but when you lift what's called "the heat sink", *that's* when the "pin block" disengages... and that's what you see when you look at the bottom of the integrated unit; the female socket that plugs into the motherboard "male" and the bottom of the processor card, so no worries. 

Now that I think about it I may unscrew the card on processor B (which I'm going to "guess" is the lower processor) to be able to examine the top of the processor for burn marks or damage..
It doesn't appear that thermal compound is used in the G5 at all... it's hard to tell from the photo's I've seen of the processor itself, and the manual doesn't mention it.

Just saw your new post while composing this. I was going to leave the plastic shunt & heatsink covers off temporarily as I can see their purpose is to force the max amount of air through, the heatsink as opposed to around it. The late G5's from the pic's I see had even more funnel shaped air "intakes" after the removable pull out fans. 

I figured as much about the clear cover, since the moment the tabs sit in* before* you close the clear cover, the fans instantly slow down. 

Can I leave one processor out for a minute & try strartup, and not damage the machine?
I'm concerned because the manual says you have to run the fabled Thermal Calibration from the impossible to find Apple Service Diagnostic Disk "whenever you replace a processor or logic board with a new processor or logic board. 
*You must also run the diagnostic if you re-install the same processor but in a different connector from the one in which it was originally installed."* 

And that's what concerns me. If I swap processors, then re-swap, I fear the system will re-set & require the CD program to be run.
I see it as a .rar file on rapidshare, but on a PPC I don't think I can use a .rar file to burn a disk as some sites suggest.


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## djackmac (Oct 10, 2009)

Windsong said:


> Can I leave one processor out for a minute & try strartup, and not damage the machine?



Refer to previous post #9.



Windsong said:


> And that's what concerns me. If I swap processors, then re-swap, I fear the system will re-set & require the CD program to be run.
> I see it as a .rar file on rapidshare, but on a PPC I don't think I can use a .rar file to burn a disk as some sites suggest.



It won't need recalibration unless you swap processor A with processor B or get a new processor. If you go back to the original configuration you'll be fine, but otherwise you'll need to recalibrate.


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## Windsong (Oct 16, 2009)

Finally had time to try again. 
I pulled and re-seated both processors 4 or 5 times. Whomever said get a 2.5 mm bit was right. 

First, in trying to asses which processor might be bad, I pulled one, then the other, leaving one processor in socket to test.
The G5 I have will not even try to start without both processors seated. No power light unless both are in their sockets.  So much for that idea...

I did try swapping them. When I do the first time I try a startup... 
*I get a single tone, lasting about 2.5 seconds* then the startup chime (this tone seems noteworthy),

... and there is disk activity and fans spinup, but after about 30 seconds, all quiets down.. nothing ever appears on the screen (screen never detects signal at all), though when left to sit for a while the upper processor seems to generate more heat than the lower one. That's just from placing my hand on the dual fans at the rear... the top one is blowing noicably more hot air than the lower fan. When they both were working, touching the rear fans at the case showed NO difference in temperature to the touch. I have no idea what that means.  

I'm assuming that the upper one is considered Proc A and the lower one Proc B
Seems logical. Before final "death" the computer showed only processor A in sys profiler.... 
as if there *WAS* no processor B.
Now without startup, I can't tell.

I finally took apart the lower processor to examine the chip itself. No outward signs of damage or burn marks. I reassembled and tried again.
Same result.

I tried pulling some of the memory (in pairs). Same result.
I tried pulling the graphics card which was bought new a few weeks ago.. just before this all started.  Apparently the same result. though without a card in, it was impossible to tell if it made a difference really, but the fans spinup, the chime, the disk activity for 30 seconds all seemed the same.      

I don't know if the card might have contributed to the failure or not. 
(My wife thinks so, I think it's a co-incidence).

I'm out of ideas. I have two SATA drives installed, one of which I upgraded to Leopard that I can't access. The other is simply formatted. 
I'm totally *NOT *getting yet another firewire box just to access the drives from my only working machine, a sawtooth G4. 

Unless it's the logic board that's causing the behavior, my G5 will not start with one processor seated.
I can't test which is the bad processor because the machine won't startup, although I assume logical design would call the upper processor "A".

Unless there's something else I could try, I seem to be at the end of what I can do. 
This hasn't been a good year for machines & I. First the MDD went.. then the replacement for that, this used G5 went a mere month into it's life.


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