Constant system crashing

Question

Hi-
I've been a proud owner of an iMac for the past 3 years. For the last 6months+, we have had constant problems with our iMac crashing. Basically, we are in the middle of doing something (or have even stepped away) and the system hangs with no response. Sometimes the current screen is just frozen. Other times, it gives a nice striped pattern across the whole screen. There's no reaction from the system at all. The only route is to do a hard reset of the system. The crashing is completely random from what we can tell, occurring once in two days or three times in one day. It's never consistent in terms of the applications we're running or what we're doing at the time. Each time, the circumstances are different.
I believe the instability started a bit with Snow Leopard installation, but I'm not 100% sure. But in the beginning, it was once in a week it happened.
At this point, I'm basically at a loss what to do without doing a complete reinstall of the system. Here's the troubleshooting I've done so far:
- I've verified and repaired disk permissions. I've verified the Disk itself.
- I've tried leaving USB devices unplugged.
- I've done a system scan via the bootdisk of the memory for any defects.
- I've done a complete clean-up of the permissions, cache, logs, etc. via Yasu. After this clean-up, we actually had a 2-3 day period without crashed, but then it started again!
- I've examined the logs via the Console and System logs. I see errors but no pattern tied with the time of the crashes, e.g. the same error messages from a particular application.
- I'm of course fully up-to-date with all Apple Software Updates.
Hoping someone can shed some light or simply confirm that I give up and reinstall everything from scratch. I'm exhausted with the crashing at this point...
I can post logs if helpful. Here's the specs on the iMac:
Model Name: iMac
Model Identifier: iMac8,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.66 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 6 MB
Memory: 2 GB
Thanks,
Joseph

Answer 1

Vents: talking about graphic card mostly, maybe iMac has air vents also, that can get clogged?
Every FREEZE or crash can = corrupt drive directory.
Heat is a primary kill-joy
For my $$ Alsoft Disk Warrior is a must, finding bad blocks is not something that Disk Utility really does - at all. SoftRAID $149 does and has SSD suport. Drive Genius 3 was reviewed today on MacFixit.
I consider iDefrag a very optional iffy add-on but useful in some situations, like making for contiguous free space to setup Windows partition.
AHT is also not going to give or find memory errors, it can detect some problems with DIMMs not functioning properly, but you would need to do an extensive test with Memtest.
I don't use or rely on or trust those Onyx type maintenance programs. YMMV but you can do better for $29 and SuperDuper (bootable backup clone software that simply skips copying temp files, logs and caches that are best created from scratch.
Too many "cooks" can spoil the brew.
From 10 yrs of using Alsoft Disk Warrior, and check the feedback reports on MacIntouch, don't leave home without, or rely on just Apple DU First Aid (or anything that is simply using the same diskutil fsck routine).
What I would do:
Clone with SD and run Disk WArrior on the clone.
Reinitialize your internal drive while booted from the SD clone external, with zero all option.
Restore.
Run Disk Warrior again.
Boot from your internal drive.
That is your best bet other than a new drive or finding all the errors are USB devices and cosmic rays. And, you get a good solid bootable backup recovery routine that supplements and improves on just having TimeMachine.