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mfox · Mar 25, 2004, 11:39 AM

Greetings. I upgraded the RAM in my Cube about two days ago by adding a 512 meg stick. Everything was fine until that night, when I started to get write and file opening errors in Word and Apple Mail. Suspecting it was a 256 meg stick that I accidentally dropped during a transfer, I pulled it and everything was fine until this morning, when I found I couldn't save a file I was working on in Word (even by cutting and pasting into a new file), and I couldn't open an attachment in Mail that I could open 5 minutes previously. Both times, rebooting made the problems go away, but I never had these problems before upgrading. One other complication - I upgraded the processor in my Cube two weeks ago. While there were no signs of trouble until I put in the new RAM, I have heard of processor upgrades operating well for awhile and then suddenly developing problems. So at this point, I'm not sure I can rule out the processor upgrade as the problem, although its recent origin does point to the new 512 meg RAM I just added. My question is whether these symptoms are classic ones for either bad RAM or a bad processor.

stuffedmonkey · Mar 25, 2004, 12:08 PM

I would definately pull the new 512 stick, put the old 256 back in, and run the machine for a while. Also you should start up in single user mode (or off of the OS X install cd) and run fsck or disk utility before testing, as disk corruption caused from one of the sticks can mess up your tests. Also you can run apple hardware test if you still have the cd. It won't catch all ram problems however...

mfox · Mar 25, 2004, 01:56 PM

Stuffedmonkey, I'm wondering about your comment of bad RAM messing up a test. Is it possible that the RAM now in the Cube is OK, but that what I'm now experiencing is corruption from the 256 meg stick that I originally pulled (the one I accidentally dropped)? If so, it sounds like I should run a disk utility first (I have DiskWarrior) and then see what happens before changing any of the RAM presently in the Cube.

ybalx · Mar 25, 2004, 02:25 PM

I had a similar experience with freaky RAM modules two weeks ago.

Perhaps 2 months ago I started noticing kernel panics in wierd places and programs. This happened around my upgrade to Panther so I thought nothing of it; feeding off some of the hype that Panther was more prone to push panics from heat problems... running panther on a 450 cube geforce 2mx card 1.5 gb RAM.

Now back to recent history. I was late on a deadline, running a new piece of software, up late at night when the crashes were more frequent. I sent the file and panic logs to the software tech -- they couldn't replicate the errors -- and I saw something in the logs that mentioned BAD ACCESS.

I pulled all 3 of the cube's 512 sticks, and one by one ran them through the G4 Cube Apple Hardware Disc. The second one failed. I replaced no. 1 and no. 3, then decided to place no. 2 back in and run the test and all three passed. And to date, not one panic with several all night sessions.

My advice, run the tests on your RAM. You should also consult the cubeowner.com forum and faq2 -- there are some more speficics on how to diagnose RAM and especially processor issues.

mfox · Mar 25, 2004, 08:34 PM

Thanks for advice, ybalx. Unfortunately, the Apple Cube Hardware Disc won't work on a Cube upgraded with a 7457 chip; it gives a logic board error (a mistake according to PowerLogix), and stops there so it never checks the RAM. I use CubeOwner all the time and I checked their FAQ, but there was nothing helpful there that I could find. What I did do is first, run Disk Utility to fix permissions, then run DiskWarrier off a firewire drive to make sure the disk wasn't corrupted by bad RAM (it wasn't as far as I could tell), and then, I pulled the new 512 meg stick and replaced it with the dropped 256 meg stick. I just did this, so it's too soon to know if the 512 is the culprit. But if anyone has a suggestion for how I could determine definitively whether the 512 stick is defective, please let me know.

But ybalx, I'm not sure I would take too much comfort in the fact that your "defective" stick isn't causing a problem anymore. It would be good to find a way to test that stick so that you know one way or the other whether it's reliable.

ybalx · Mar 25, 2004, 09:10 PM

I hear you on the hypothesis -- I believe that I had a DIMM slightly out of alignment or some static electricity had built up, and was discharged as I grounded the module out of the board.

I didn't realize the 7457 didn't run the apple app. I did read about an old ram check app in OS 9... did you check into the system kernel panic logs? I don't recall whether Microsoft maintains an error log too. Perhaps ou can find some clues.

Sorry no more help from me. :/

eyadams · Mar 26, 2004, 11:14 AM

I had a similar problem years ago - I had upgraded RAM and an upgraded CPU, and kept getting weird crashes. The problems occured under OS 9 and OS X, and under multiple installs of both, so I was confident the problem was with the hardware.

What you need to do is figure out some kind of test that consistently locks up the computer. I recommend games - especially a game where there's a rendered splash screen that you can play over and over. When I had my problems I used the castle flyby sequence in the first Unreal game - it's a good stress test.

Then start testing. You have two variables - possibly bad RAM, and possibly a bad CPU, and both are possible. Restore the machine to stock and run your stress test. Put in the new ram, run test. Put old ram back, put in new CPU. And so on. Run through all permutations, not just the ones that target your ram and cpu - it might be some other component, or a combination.

mfox · 09:09 PM

Well, I ended up not doing anything very sophisticated; I just removed the 512 meg stick and put back in the 256 meg stick that I had accidentally dropped. I did this last night, booted up a lot of applications to reduce free memory and force pageouts. So far, 24 hours later, none of the problems I reported have re-occurred. While it now appears that the 512 stick is the culprit, I don't feel as though I'm out of the woods quite yet. I'll give it some more time before sending back the memory, and even if everything works fine as a presently have it, I'm going to try popping that 512 in another slot or another Mac just to see if the "recessitation" of ybalx' "bad RAM" might yet happen to me. Thanks, all, for the suggestions.

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Uh-oh; spoke too soon. Problem did return, once again solved by a restart. Seems like too much of a coincidence for the problem to be due to both the new 512 meg RAM stick and the 256 meg that I had dropped. Could this be a problem with the processor upgrade? If so, why would it go away following a restart?

reader50 · Mar 26, 2004, 11:02 PM

Try reseating all RAM sticks a few times. Dust can comtaminate a RAM slot, especially if the slot had been empty for a long time. It might take a few seating attempts before all pins are making clean contact.

The machine warming up could be enough to move a marginal contact into an unreliable contact. This is one reason why RAM sticks sometimes test bad, get put back in, and test good thereafter.

This is only one theory, you may be busy for awhile trying to track down an intermittent problem with RAM or CPU or other. For example, check the HD cable connections. A loose cable header left over from the CPU upgrade can cause all the symptoms you have described.