[rzwitserloot]

My iBook freezes up intermittently. When it does this, the mouse cursor no longer moves, all applications stop responding, itunes stops playing, etc. The caps lock and num lock lights still work, but that's about it.

I've run memtest for 10 passes (8 hours worth of memtest) and it did not find any troubles - nor did it crash during its operation. I ran it in single user mode as the manual for memtest suggests.

The freezes are slightly more likely when I resume from sleep (I open the ibook, the sleep indicator light goes off, but nothing else happends - only way out is to hold power for 4 seconds and restart it).

All this happend about 2 weeks after i put some old 256MB SO-DIMM I had lieing around (PC2100 even) in my iBook. iBook froze up after about 5 minutes of operation (3 times). At this point I removed the SO-DIMM, and now the freezes occur on average after 6 or 7 hours. I have this iBook since october, and it hasn't ever done this until now.

I would have bet good money its a memory problem, but, as I mentioned, memtest can't find anything.

Does anyone have any idea on what might be causing this? It's not heat dissipation either; there seems to be no relation.

I have the 1.33Ghz G4 iBook 12" with built-in AirPort and Bluetooth, which is as far as I know the newest 12" basic iBook model.

[psk-ele]

Well, your first mistake was using the PC2100 memory. Your iBook is indeed the newer version and runs on PC2700 (333MHz) DDR SDRAM. I am not sure what effect this would have on the iBook (anyone?).

My first thought was indeed heat dissipation problems, but since you have ruled that out....my only other thought is hard drive problems. If you have used the Activity Monitor to rule out a rogue process (some program using up a significant portion of your CPU speed) then my guess is your hard drive could be dying. A few tell tale signs would be a grinding noise coming from the HD or longer boot times or no booting at all.

Also, you could try to run Apple's included Disk Utility program and do a "Repair Permissions" Another good idea would be to down load Cocktail http://www.maintain.se/cocktail/index.html, and run all the included scripts (this just runs the various maint. scripts that Unix runs daily, weekly, and monthly. Also it runs a prebinding and repair permissions script) If that does not solve your problem, I would tend to go back to a HD issue. If you have Disk Warrior (or Drive 10) you can use that to determine the status of your HD (the HD has a S.M.A.R.T. chip that determines an imminent failure of the HD).

This is only my guess, maybe someone else on this forum could give a better diagnostic of your problem, especially since I use a 12" PB (also 1.33 GHz) and not an iBook.

Hope this helps get you pointed in the right direction at least!

Good Luck!