Matching RAM

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Level 1

1 points

Matching RAM

Does having different sized pair of RAM sticks cause issues. I started with 512 RAM nearly 3 years ago and added 2 1gig sticks.... never really had a problem... about a year ago I added 2 2gb sticks for a total of 6.5 gigs. I've noticed an ever increasing issue with random freezing... and just lately it has gotten unbearable. In my troubleshooting, I took out all the aftermarket sticks leaving the 256 sticks and the computer wouldn't even turn on. I switched it out to where there was the 2 pairs... the 1 gb, and the 2 gb... and the computer turned on but was having seriously issues. I am not running on just the pair of 2gbs, and it "seems" alright. My question is, is there a problem with having multiple pairs of different sizes etc?

Posted on Sep 16, 2008 4:07 AM

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Answer 1

Sep 16, 2008 4:33 AM in response to BleedingStar

Hi BleedingStar-

+I am not running on just the pair of 2gbs, and it "seems" alright.+

Something wrong there. The G5 Power Mac shouldn't be able to use 2GB sticks. If you select "About this Mac how much RAM is indicated?

Is the RAM installed in matched pairs and in the correct slots?

If you haven't already seen it this may be helpful: G5 Memory Replacement Instructions

Luck-

-DP

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Answer 2

The hatter

Level 9

60,990 points

Sep 16, 2008 4:54 AM in response to DaddyPaycheck

The late 2005 G5 though, does accept 2GB density. And of course sometimes what wasn't a supported configuration or tested "might".

http://support.apple.com/kb/SP37
http://support.apple.com/kb/HT2248?
http://www.apple.com/support/powermac/

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Answer 3

BleedingStar Author

Level 1

1 points

Sep 16, 2008 4:55 AM in response to DaddyPaycheck

I am using a G5 Power Mac Quad 2.5. It does take up to 16 GB of RAM with 2 GB sticks in the 8 slots. They are in the proper slots and in pairs only. The question is wether having 3 different pairs can cuase a problem.

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Answer 4

Sep 16, 2008 6:24 AM in response to BleedingStar

My bad. Thanks hatter.

Having 3 different pairs shouldn't cause a problem when installed as you describe.

It is possible for RAM to fail.

Luck-

-DP

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Answer 5

The hatter

Level 9

60,990 points

Sep 16, 2008 7:12 AM in response to BleedingStar

Crucial found that mixing memory from different batch/builds or lots, along with mixing different vendors, can even today not get along.

I would try with just each set individually, and reset-nvram before each fresh configuration.

There can be differences enough that brands A + B + C only work alone, or that C works with A but only when B is not present.

Dimming variation, latency, programmed SPD, harder to match than any DNA.

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Answer 6

BleedingStar Author

Level 1

1 points

Sep 16, 2008 7:39 PM in response to The hatter

Well, it is obvious that my RAM is picky about the order and combination that it is used in... because it is actually running faster with the single pair of 2 gb sticks than with the combination of all 3 pairs for 6.5 gb of RAM.

However, sadly... my computer just locked up on me again even with just the single pair. I am still trying to crack down on what is causing this problem. My box was kinda dirty inside by the CPU, so i got some compressed air stuff and cleaned it out... maybe that explains the progressive increasing of the problem? I dunno... i also unplugged all peripherals to see if they were part of the issue. It's all about troubleshooting now.

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Answer 7

BleedingStar Author

Level 1

1 points

Sep 16, 2008 9:47 PM in response to BleedingStar

****... just froze again.... even with being cleaned and all peripherals detached.... maybe the video card???? ugggg... this is lame

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Answer 8

japamac

Level 7

24,400 points

Sep 17, 2008 3:54 AM in response to BleedingStar

Hi-

Run the Apple Hardware Test from your install discs.

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Answer 9

BleedingStar Author

Level 1

1 points

Sep 18, 2008 5:16 AM in response to japamac

Just did a full Hardware test... everything passed with flying colors? That mean its gotta a be a software conflict?

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Answer 10

japamac

Level 7

24,400 points

Sep 18, 2008 7:13 AM in response to BleedingStar

Just did a full Hardware test... everything passed with flying colors?

That's good... for a start.

Download and run Rember or Memtest to re-test the memory. Both do a better job than the AHT.
Run the RAM tests in loops, 10 or more iterations, to thoroughly stress test the memory. Random errors may not be caught in a single pass test cycle.

Should additional RAM testing prove to be error free, and with the AHT not reporting logic board, VRAM or other errors, one may be able to focus solely on possible software issues .
However, hard drive sector damage or sporadic CPU trouble could still be the cause...

I would for now, focus on the hard drive, and the possibility of corruption within the data for system software- the OS.
Disk Utility provides verify and repair options for the hard drive.
DiskWarrior can do much better.

If you have Tech Tool, try it.

A severly corrupt system can be irreparable, with erase and install as the best option. Even if repaired, sector damage would continue to cause problems.
To rule out possible sector damage (and the data contained within those sectors) as the source of your troubles, a security write with zeros (1 pass) would map out bad sectors, and disallow use of those areas in subsequent software installs.

If the drive is 4-5 years old, simply replacing it would probably be better.

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Answer 11

BleedingStar Author

Level 1

1 points

Sep 18, 2008 10:31 PM in response to japamac

Alright, well i've ran about 7 loops out of 10 on the RAM, and everything has been OKAY on all accounts.

In a previous discussion from someone with a similar problem, someone had mentioned their issue being with their kernel_task. I looked up a bit about kernel_panics.

I just looked in my log... and i have over 100 kernel panics in the last 3 months... 20 in the last week. The logs all very put most look similar to this:

Wed Sep 17 22:30:06 2008

Unresolved kernel trap(cpu 1): 0x300 - Data access DAR=0x0000000000000000 PC=0x000000000000B9CC
Latest crash info for cpu 1:
Exception state (sv=0x63069780)
PC=0x000009CC; MSR=0x00001030; DAR=0x00000000; DSISR=0x42000000; LR=0x00042130; R1=0x62D93D50; XCP=0x0000000C (0x300 - Data access)
Backtrace:
0x00452224 0x00002124 0x00356AA4 0x000B05D4
Proceeding back via exception chain:
Exception state (sv=0x63069780)
previously dumped as "Latest" state. skipping...
Exception state (sv=0x1101c80)
PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)

BSD process name corresponding to current thread: kernel_task

Mac OS version:
9E17

Kernel version:
Darwin Kernel Version 9.4.0: Mon Jun 9 19:36:17 PDT 2008; root:xnu-1228.5.20~1/RELEASE_PPC
System model name: PowerMac11,2
panic(cpu 0 caller 0xFFFF0003): "wait queue deadlock - wq=0x46ebec, cpu=0\n"@/SourceCache/xnu/xnu-1228.5.20/osfmk/kern/wait_queue.h:169
Latest stack backtrace for cpu 0:
Backtrace:
0x0009B498 0x0009BE3C 0x00029DD8 0x00042750 0x00356168 0x007A39A4 0x0035A414 0x0061F928
0x0036FEA4 0x000B4BF4 0x000B30B8
Kernel loadable modules in backtrace (with dependencies):
com.apple.NVDAResman(5.2.8)@0x79e000->0xa1efff
dependency: com.apple.iokit.IONDRVSupport(1.5.2)@0x786000
dependency: com.apple.iokit.IOPCIFamily(2.4.1)@0x609000
dependency: com.apple.iokit.IOGraphicsFamily(1.5.2)@0x760000
com.apple.driver.AppleMPIC(1.5.3)@0x61d000->0x620fff
dependency: com.apple.iokit.IOPCIFamily(2.4.1)@0x609000
Proceeding back via exception chain:
Exception state (sv=0x631d1500)
PC=0x000B66DC; MSR=0x00009000; DAR=0x52846504; DSISR=0x00200000; LR=0x00035854; R1=0x62D53CF0; XCP=0x00000014 (0x500 - Ext int)
Backtrace:
0x00035830 0x000360A0 0x00036BD8 0x00356B3C 0x000B05D4
Exception state (sv=0x588c5780)
PC=0x00000000; MSR=0x0000D030; DAR=0x00000000; DSISR=0x00000000; LR=0x00000000; R1=0x00000000; XCP=0x00000000 (Unknown)

BSD process name corresponding to current thread: kernel_task
/

I have no idea why this is happening.... and 3 times a day is an obvious problem.

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Answer 12

japamac

Level 7

24,400 points

Sep 19, 2008 2:18 AM in response to BleedingStar

Hi-

Could you please post with your machine specs- model, CPU, graphics card, current OS, etc.?
It would help in further troubleshooting suggestions.

The KP report seems to indicate involvement of some graphics kexts.
The "com.apple.NVDAResman" is noted in graphics card failures in other forums searched in Google.

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Answer 13

BleedingStar Author

Level 1

1 points

Sep 19, 2008 12:58 PM in response to japamac

Hmmm, interesting....

The current system is:
Quad G5 (late 2005) 2.5
OS X version 10.5.5
RAM; 2- 2 GB sticks, DDR SDRAM ECC, PC2-3200E-288
Graphics Cards: 2 Nvidia GeForce 6600 (one came stock, added the second)

I am currently running a 4 display setup, 3 19" monitors and a projector display.

That makes sense that NVDAresman would have something to do with it.

I currently am testing the system on a test user account to see if it still panic... thus trying to figure out if it is related to any personal prefs, etc used on my other user.

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