24" iMac Screen Freezes since 10.6.3 update - pls help!

I remember using the information in these some time ago:

http://support.apple.com/kb/ht3696

The terminal command to permanently set iMac to boot into the 64 or 32 bit kernel:

http://support.apple.com/kb/ht3773

What are the pros and cons to running 32 Bit versus 64 Bit on our iMacs anyways? BTW, 24 hours+ and no freezeup yet.

32bit only allows you access upto 4Gb of memory and usually means that the video memory has to be mapped/overlapped with the system memory. e.g. if you have 4Gb of system memory and your graphics card has 512mb, then you'll only be able to use 3.5Gb of your system memory. I'm not sure if this is correct for OS X, but it certainly is for Windows.

64bit allows you to address memory greater that 4Gb and means that your video card memory doesn't have to overlap your system (as above, I'm not sure if that's just a Windows problem). You also get a performance increase with 64bit apps, which was demonstrated at the WWDC a year or two back, but can't remember the reason for it.

I'm not sure what the issues are around here with 32/64 bit and 7,1 models, as that model is fully 64bit (both EFI and processor), which is why it can run Mountain Lion and Mavericks (and theoretically any future 64bit OS X). See here.

6,1 models, however, are only half 64bit; 32bit EFI and 64 bit processor, which is why you can't get above OS X Lion (although you can do it with a hack).

Swampy...

Thanks for th explanation LOL. I was worried that if I ran in 64-Bit mode 24/7 then I might actually slow down my mac rather than make it more efficient. So even though Apple says 4 Gigs is max maemory for my machine, I am running 6 Gigs and its recognized. My primary "application" is Adobe CS4 and mainly Photoshop CS4. I don't do much of anything else in the way of extra programs. I think CS4 will run under 64-Bit OK... but I will have to check. I know it works, but whether its working well is unknown.

Its been 3 days since the fix and no more freeze-ups I'm happy to report.

Mike

Now there seems to be a similar problem with AMD GPUs in Macbook Pros.

http://www.macrumors.com/2014/01/17/2011-macbook-pro-gpu-glitches/

Personally, I'm going to be very wary of buying any more Apple products with AMD/ATI graphics in them, which is to say na gon do it.

*update....

I looked into my issue more and found that I wasn't actually deleting the AMD files when I dragged them out of the system folder.

* you must right click and choose delete. This will prompt you for admin. approval and password.

My ATI files are now showing enabled and I haven't had a freeze in 48 hours. 🙂

Dave

Yeah... Well, unfortunately, I had a freeze-up yesterday which was 8 days. Better than every 2-3 days but still a PITA. I don't remember if I truly deleted any files or what. I may have to repeat the process just to be safe if there's something creeping back in.

Its my understanding that Mavericks boots in 64-Bit mode automatically right? Or do I have to set some parameters to make sure it does. I was only worried about about my Adobe CS4 suite, but so far Photoshop hasn't burped.

Mike, this might help you see if your iMac can be made to boot automatically into 64-bit mode. I have no idea if Mavericks automatically boots that way, or if it is machine-dependent.

http://macperformanceguide.com/SnowLeopard-64bit.htmlhttp://macperformanceguide. com/SnowLeopard-64bit.html

Another Update: going on my 4th day without one Freeze.

Seems that the Kext fix works with 7,1 iMac running 10.9.1 🙂

Well, still no freezes since Feb. 22nd.

I'm thinking the kext has stopped my random freeze problem again. 🙂

Dave

Jan. 22nd - right, Duster19?

Opps... Yeah Jan. 22nd.

🙂

Hi

I have an early iMac 24 with ATI Radeon pro 2600. I have been running 10.9.1 with no problems since Maverick OS came out. The screen freeze problem during Netflix happened 2 weeks ago, then again 2 days later. Finally, I got the "white screen of death". Booted into safe mode and applied the "kext" fix mentioned on this post (moved/replacedcurrent AMD, ATI kext files with the older versions as suggested). Now, I am back to a functioning computer (still running 10.9.1). However, performance did slow down quite a bit, everything is slow to load; faint, vertical, red lines are visible in front of gray background (iTunes, outlook, etc).

What does this "kext" fix do? Am I not using my ATI Radeon graphics card anymore? Do I need to replace the graphiscs card or is this a software problem?

Semih_TX - I did not experience your issues with the slow loading and faint lines. The kext fixes install old software drivers for your graphics card. You are using your ATI card, just with drivers from a few years ago -- before Apple upgraded them in a way that causes the graphics card to crash the system. You don't need to replace the graphics card, so long as you use the old drivers with it.

Anyone install 10.9.2 yet? Does it require a reloading of the old kext files, or does it leave those files alone? Thanks.