iMac freezes

18 posts
24 Feb 2014
diipii
Photographer
diipii
My old iMac 2.16Ghz Core 2 Duo OS 10.6.8 regularly freezes when playing HD videos on YouTube and parts of the page corrupt into random patterns. It will un-freeze by itself after a minute or two and I suspect overheating graphics not keeping up with BT Infinity but smcFan control says 27C which does not seem excessive. The problem is gradually getting worse. Any help would be hugely appreciated.

Posted 24 Feb 2014
magpie1
Photographer
magpie1
Another problem, might, be the HD starting to fail! Sorry, but they were the first symptoms when mine went.

Posted 24 Feb 2014
diipii
Photographer
diipii
Thanks for the reply. I did suspect HD trouble but have heard nothing untoward from that area. Might be another good reason to buy a new Mac with SSD.

Posted 24 Feb 2014
magpie1
Photographer
magpie1
Have you tried running Disc Utilities, repair permissions?

Posted 24 Feb 2014
diipii
Photographer
diipii
Yes, and reset SMC and PRAM

Posted 24 Feb 2014
anthonyh
Photographer
anthonyh
How much memory (RAM) is installed?....memory is cheap so I would max it out if you haven't done so.

Posted 24 Feb 2014
diipii
Photographer
diipii
Max ram fitted and working OK. It's only 3mbs on this machine.

Posted 24 Feb 2014
RedChecker
Photographer
RedChecker
Is the processor actually fast enough to play HD video? (Core 2 Duos are pretty old hat now)


Posted 24 Feb 2014
diipii
Photographer
diipii
RedChecker
Is the processor actually fast enough to play HD video? (Core 2 Duos are pretty old hat now)
Thanks, I think you might have hit the nail on the head with this suggestion. The iMac copes well with iMovie editing, Skype and CS3 etc but shows its age with HD video from the net. It can play HD but I suspect it taxes it beyond it ability to play it for long periods, hence the apparent overheating. I am watching with interest the development of iMacs and might plump for a new one in about 6 months when the next incarnation is due. Nearly all my TV is watched on the iMac these days so it wont be such a big decision.
Posted 24 Feb 2014
anthonyh
Photographer
anthonyh
diipii

Max ram fitted and working OK. It's only 3mbs on this machine.


I would say this is a big part of your problem....if that is your standars RAM  then the video card probably has next to nothing or even relies on system RAM rather than dedicated video RAM.

You need a bigger machine from the modern era... surprise
Posted 24 Feb 2014
CSD_Images
Photographer
CSD_Images
The main areas from my experience are:

HDD is failing, iMacs went through a rough patch with Seagate drives that would fail. Particularly the 1Tb. I knew one owner who went through 3 drives before Apple replaced it with a SSD in the end.

The other issue I've seen in OSX 10.8 and 10.9 is a weird glitch in kernel to access the drives, which Apple patched so ensure that your system is up to date. May affect older versions of OS X as well.

Dodgy nVidia graphics chips. Rather infamous chapter for nVidia in that a major portion of nVidia graphics chips failed due to substrate issues. This affected a lot of PCs and Apple computers. The faults varied but generally it was graphic corruption, system shutdowns, screen freezes and black screens. This occurred from 2007 through to early/mid 2009.

Out of all the above, the HDD is the most likely culprit especially if it's an old machine. I tend to retire my hard drives after 3 years especially system drives as that's when the chances of failure exponentially increases.

Posted 24 Feb 2014
diipii
Photographer
diipii
Well noted. I will listen/watch for any hard drive "events". I wouldn't fancy changing drives on a Mac every 3 years ! They are not the most user serviceable machines but I take your point.
Posted 24 Feb 2014
diipii
Photographer
diipii
anthonyh
I would say this is a big part of your problem....if that is your standars RAM  then the video card probably has next to nothing or even relies on system RAM rather than dedicated video RAM. You need a bigger machine from the modern era...
The graphics card has only 128mbs so steam powered compared with today's machines !
Posted 24 Feb 2014
doughnut
Photographer
doughnut
Processor has little to do with it.

I have a Core 2 Duo pc running Windows 7, and with a dedicated graphics card (with 1GB graphics RAM) it can run HD with absolutely no stutter at all. And that was before I upgraded the pc RAM from 1GB to 4GB!

Posted 25 Feb 2014
RedChecker
Photographer
RedChecker
doughnut

Processor has little to do with it. I have a Core 2 Duo pc running Windows 7, and with a dedicated graphics card (with 1GB graphics RAM) it can run HD with absolutely no stutter at all. And that was before I upgraded the pc RAM from 1GB to 4GB!


You do realise that video cards often have routines built-in that massively accelerate the decoding.  Since this is an old laptop it may well be that said acceleration for HD video isn't present and MAY be relying on fully decoding the video using the CPU alone (wheras your PC may be using GPU acceleration).
Posted 25 Feb 2014
Edited by RedChecker 25 Feb 2014
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