Freeze of screen randomly on Macpro early 2008 !

Question

Hey,
I'm owner of a Macpro early 2008 that worked fine since three years now. Since few weeks it has started to develop a strange "bug". Randomly, after few minutes, or hours, or sometimes never during the day (I shutdown my computer in evening and put it back on in the morning), the two screens plugged on Macpro freezes. When it happens, each both screens connected each one on a separate graphic card freezes but mouse cursor can still be moved on screen and computer is still running as I can still hear music playing !
I didn't find any link between applications or what I do on computer with occurence of that strange freeze !
Any ideas ? I tried to plug both screens on same graphic card thinking it might be the Geoforce graphic card that has some issues but same problem ! It looks like problem occurs more and more often these last few days. Looks like something is dying
Thanks for your ideas,
Vincèn

Answer 1

I've exact same problem with my mac pro 2010, but my problem still persist. My spec is 2 x 2.66 Ghz, 2 x 1TB SATA Hard disk, 8 GB of DDR3 ram 1333 Mhz. I am using a different graphic card which is ATI Radeon 5770 HD. with only 1 display and I've done intense gaming on bootcamp windows 7 64bit without any problem except with the AppleHFS.sys file.
Here is what I've done which might help you problem:
Boot into safe mode by holding shift key during bootup and see if the freeze still occurs. If it doesn't It's more likely due to your 3rd third kernel extension.
Check the Console application located at Appplications>Utilities> and see if there are any diagnostic error relevant to the freeze. (i.e. look the time stamp of each message and compare to your computer reboot time stamp.
Use disk utility and check errors for your drive. Click on the actual hard disk rather than the partition volume and click on verify disk, if there is a lot of red error message, means your disk have serious problem. Repair disk will not work if it's located on the same boot drive. But you can boot from the mac OSX installation DVD by pressing and holding C during boot.
After you booted from the hard disk, choose your language and click next. Then you will see a menu bar on top of screen. Click on utilities and then click on Disk utility. On the left hand side is a list of the disk detected by you mac. Click on the boot drive (not the volume), and check the S.M.A.R.T status of the disk. If its verified it may be okay. Then click on verify disk to check the disk for error. If you see a lot of red message from the log, it means your disk is corrupted. Try and use disk utility and click on repair disk to repair the disk.
If Disk Utility fails, there is another 3rd repair tool called diskwarrior. I've never used it. and it cost ~$99 USD for full version. Apparently it's the best software to mac to check disk error and repair.
If all your disk seems to be normal, I'd use superduper to backup your data and do a clean install of OS X from the installation disc again. If your problem persist. Try to use the apple hardware test, which is on the application installation dvd that comes with your mac, insert it into the dvd driver and boot while holding D button. When they AHT is ready, press ctrl + L to set it into loop mode. and let it run over a long period of time. It will stop when it encounters an error or hardware problem. This will detect faulty hardware, but I don't think it works on graphic cards.
If the above mentioned steps do not work for you, I suggest contacting AppleCare. I've been experience exact same problem with os x 10.6.7 SL. I've done all the above steps and problem still persist. Did a looped AHT overnight with 8 passes without encountering any error.
I am suspecting bad batch or memory modules or bad motherboard. My problem pops up randomly and hard to reproduce, sometimes I can be only all day without any issue, and sometime it procured right after boot or clean install of os x. It even happened once when I was booted from the installation DVD.
But I was using after market peripheral mouse and keyboard, I've reverted back to apply default keyboard and magic mouse to see if it is the logitech G19 or Razer Epic Naga mice that's causing the problem.
So far, I ruled out the G19 keyboard as using the Naga Epic Mice along also procured a freeze, (not sure why, but Mac detected the naga mice as a keyboard probably due to the keypad on the side.) It tried to make me identify the keyboard as I plug in the razer mic, but as it has no z and / button I could not finish the identification process.
Before that, I was using the G19 keyboard and the Razer mice simutaneously, After swtiching and using either one of them made me realsed that the Keyboard identification on OSX is not for the G19 but instead for the razer. I've been foolishly using the G19 keyboard for the keyboard identification process. I am not sure if this is the cause of the my freezing problem (2 x keyboard detected and G19 keyboard used to identify the naga epic mice).
Try the steps I mentioned above and see if it fixes your issue, and can you let me know if you are currently using any after market keyboard and mice, cause if you do... it will help me narrow down my problem before I have to wait in a long queue on line for applecare to check my problem and tell me to do things that I've already done.
Cheers.