# Power Mac G5: Unexpectedly Quit, Kernel Panics, Bad_Access_Errors



## Clever321 (Jun 7, 2009)

Greetings,

I am running a Power Mac G5 2.5 GHz Dual-Core with two 512 MB DDR SDRAM. Looking to upgrade my overall performance, I purchased two 1GB sticks of compatible DDR SDRAM. About five to ten minutes after installation I began getting serious Kernel Panic and EXC_BAD_ACCESS errors in almost every application. Naturally, I assumed it to be bad memory. I sent back the RAM, received new RAM, and installed the two sticks only to begin having the same problems about five to ten minutes after installation. Figuring I couldn't be so unlucky as to receive two bad sticks in a row, I ran a TechTools inspection of my whole system and found nothing. I ran a disk repair, permissions repair, and even went so far as boot off Disk Warrior and do a restore of my HD. The problems continued. Next I assumed I had faulty RAM slots. I exchanged the RAM in every combination conceivable, old sticks in 2nd slots, new sticks in 1st slots, only new sticks in 1st slots, only new sticks in 2nd slots, etc., etc. The only combination that didn't cause problems was old sticks in any RAM slot. It became clear that I did not have any faulty RAM slots.

So, I refunded the RAM and decided to order from Crucial. The two 1GB DDR SDRAM arrived, I installed it, and the same problems arrived five to ten minutes after installation. Random "unexpectedly quits" by fault of EXC_BAD_ACCESS errors and the occasional Kernel Panic. I did the whole process of RAM slot swaps once again, new sticks in 1st slots, old in 2nd, new sticks only, etc., etc. Once again, the only working combination was only old sticks in any slot. I decided to return the RAM and try again with two new sticks. They arrived today, and the exact same problems have occurred, starting within the first five minutes after installation.

What the heck is wrong with my computer? Can i really be so unlucky as to receive 8 bad sticks of RAM in a row? 

My computer worked and still works fine with only the two 512MB sticks installed in any slot.

This has been a long and painful process, so any suggestions/solutions would be greatly appreciated.


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## sinclair_tm (Mar 11, 2005)

The problem is that some Macs are very picky about RAM. In my experience, there is only one place that I trust to buy Mac RAM from, and that is www.macsales.com, because Mac upgrades is all they do. Also, are you sure you got the correct RAM? There are two 2.5Ghz G5s, and they both take different RAM. Do you have the two 2.5Ghz G5 CPU model that takes PC3200 RAM, or do you have the two dual core 2.5Ghz G5 CPU model that takes PC2-4200 RAM? To find out, click on the Apple menu and select _About This Mac_, and then click the _More Info..._ button. In the window that pops up it will list some info about your G5. What you want is *Number Of Processors:* and *Total Number Of Cores:*. The two CPU model will have 2 processors and 2 cores, while the two dual CPU will have 2 processors and 4 cores.


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## Clever321 (Jun 7, 2009)

This is exactly what my "about this mac" reads:

Model Name:	Power Mac G5
Model Identifier:	PowerMac7,3
Processor Name:	PowerPC G5 (3.0)
Processor Speed:	2.5 GHz
Number Of CPUs:	2
L2 Cache (per CPU):	512 KB
Memory:	1 GB
Bus Speed:	1.25 GHz

and for memory ...

DIMM0/J11 512 MB DDR SDRAM PC3200U-30330 OK
DIMM1/J11 512 MB DDR SDRAM PC3200U-30330 OK

So can you translate that? Does this mean I have the Two 2.5GHz CPU? I think so...

For all the sticks I've tried, they've all read DDR SDRAM PC3200U-30330 OK.

Any other possibilities besides just more bad RAM? Perhaps a motherboard problem?


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## sinclair_tm (Mar 11, 2005)

Okay, you have the two G5 CPU Mac, not the two Dual core G5 CPU. I know that the Macs are picky about how the RAM sticks are set up. If they have the wrong number of chips, or wrong arrangement, you'll have issues. I'd return them and try RAM from Mac Sales (aka OWC). IF you get the same errors with that RAM, then I would for sure say it's the motherboard, at which point you will need to take it to an Apple service center so that they can test it for sure.


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## Clever321 (Jun 7, 2009)

Thank you very much for your help. I'll let you know how it turns out with the new RAM. Unfortunately i wont be replacing any motherboards for my 5 year old computer, so perhaps it's time for a new model.


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## backup15andpunt (Aug 28, 2009)

Clever321 said:


> Thank you very much for your help. I'll let you know how it turns out with the new RAM. Unfortunately i wont be replacing any motherboards for my 5 year old computer, so perhaps it's time for a new model.


I might be able to help but I need to know what OS version you are running first.


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