PC user trying to upgrade friends Mac...


And I'm about to lose it but before I blame the OS and hardware, maybe there is somthing I'm missing - as to the problem of freezing and lockups during local LAN access or when doing a few things at once (surfing while running an installer while listening to music of the local drive..etc. I dont mean freezing as temporary slowdowns but beachball spinning and cannot even bring up force quit or anything...just can move the mouse and nothing else. Oh her OSX is old as well. Its version 10.2 which I have updated to the latest security updates..etc.

The computer is old. Its a B&W G3 400Mhz with 512mb of PC100 memory and an 18gig 7200RPM SCSI drive off an older ATTO UW Controller. The system was stable in OS9. Just as a test I took the memory and one by one tested it using Memtest86 in my PIII 500Mhz box and they pass. I should mention that none are actual apple memory but I'd assume they are fine. Two dimms have LG chips and one has Micron. I dont think its cable or termination of SCSI or else it would freeze in OS9 as well. The only thing I have not checked is the computer's firmware.

Anyway its more unstable right now than Windows 95 with all mystery parts put together by a monkey :( Might it be the SCSI controller - meaning it may not have proper support under OSX?


Mac of the SubGenius! :-)
The only thing I can think of is that it's the memory. OS X is very picky about RAM timings. While Windows might not care as much about minute timing differences, OS X doesn't do well with it. Even though the memory is sure to work fine, the difference in timing between the two memory chips (especially if they're from different manufacturers) might be the cause of the problem.

The other problem might be the SCSI controller. Are you sure that SCSI controller is well-supported under OS X? Is it possible that ATTO might have some updated OS X drivers for that controller?


I have the same machine at home. It uses a Apple-supplied UltraSCSI controller with an old 9gb Cheetah HD, and I have upgraded it with an extra 80gb Seagate ATA drive.

Like the previous poster said, Mac OS X is picky about RAM. However, the OS will do a system check on your RAM at startup and if it doesn't like it for any reason, it will not use the RAM. This caused a lot of anger with people who suddenly went from a full gig down to 256mb after a system install.

Because of this, it doesn't sound like RAM to me. The OS wouldn't even access it if the RAM had a problem. Have you ran a disk utility on it to check the hard drive? Mine got real jittery under 10.2 Jaguar and the cause was a lot of problems on my main drive (I ended up wiping it). Does the G3 also have an internal ATA hard drive? The ATA chipset on this particular Mac has known issues that are addressed in a firmware update. The problems include random data corruption.

If you have installed all the firmware updates and you do have an additional drive on the computer, try installing OS X on that additional drive, set it up for normal use and boot off of it. If you get the same crap, then perhaps you do have a RAM or other hardware problem. If it feels smooth, then you have your answer. I would serously suggest putting a cheap ATA drive on this machine, if for no other reason than using it to do quick-n-dirty backups and having another drive to boot from. Big ATA drives that are compatible with it can be had for cheap at places like Wal-Mart.

Captain Code

Staff member
How much hard drive space is left? Keep it mind that's a fairly old computer and OS X won't be that fast on it. You probably won't be able to play a lot of divx files as my brother has a B&W G3 300MHz and it's slower than I could ever put up with.


Thanks guys for the prompt reply. I'm going to go ahead and put the computer to the latest firmware. I'm only running the one drive (SCSI) and no ATA drives in the machine. There is about 1/2 the drive left for free space. Also I did find out as someone else said, the SCSI card seems to be an apple supplied unit. I'm not sure if its just UW or U2W but doesnt matter with the one drive in there. The cable does have an LVD term as well.

I'm going to disable all power saving as well incase the computer doesnt behave well after going to sleep and waking up....