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Level 1

114 points

27in iMac (late 2009) ATI 4850 drivers problem in Windows 7

This iMac is less than a month old. Windows 7 was working fine until a couple of days ago. While at the Windows 7 desktop the screen pixlated and froze. A tip bubble appeared in the notification bar that said the ATI driver quit but was recovered. The screen went black then restored itself. A moment later the whole thing occurred again. Is this a known issue? Is there a fix? Thanks for any help.

iMac, core i7, 16gb, ATI 4850, Mac OS X (10.6.2), boot camp w/ Windows 7

Posted on Feb 10, 2010 9:24 PM

Best reply

thebigears

Level 1

5 points

Posted on Feb 12, 2010 3:20 AM

there are well known issues with iMac 27 (late 2009). There are heaps of threads on this issue.

basically do the following:

1. install windows 7. most people get stuck at this point, due to the windows installer not having compatible drivers for ATI Radeon HD 4850 graphic card. Which apple has a fix for. search this forum if you need help here. it involves loading certain files on a USB stick or SD card and making available during windows 7 install.
2. install bootcamp drivers that came with snow leopard. (ie version 3.0). just put in snow leopard install disc whilst in windows and let autorun find setup.exe
3. then install bootcamp drivers version 3.1
4. then go to control panel, system, device manager, display adapters. double click 'ATI Radeon HD4850', click driver. (at this stage your driver should be version 8.681.0.0. You need to downgrade driver to the version it was before bootcamp 3.1. so click update driver and put in your snow leopard installed disc again and search. you should end up with version 8.661.0.0.

hope this helps.

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20 replies

Jul 24, 2010 6:21 AM in response to malku

I struggled with this for ages, then found that for the drivers I had used a Snow Leopard DVD (a retail DVD, I think), but not the one that came with the particular iMac. If you use the disk that came packaged with the particular iMac, the drivers should work out fine, in my experience.

HTH

Adam

Sep 1, 2010 4:14 PM in response to MacChris

malku wrote:
Hi
I have installed several times Windows 7 on my imac 27 with ATI Radeon HD 4050. I want to try what you did, downloaded the catalyst 10.4, but still don't know how to install manually 8.723.0.0 is't the one that comes with Catalyst 10.4 or do I have to roll back to another driver version like explained in other discussions?.
Please help me, I need to get working with Autocad 2010.

I've been waiting for the answer, Would you pls post it here? Thank you! Anybody can answer it?

Buhu

Level 1

0 points

Sep 27, 2010 11:47 AM in response to Jackson.Burstyn

I was looking for this answer myself.
After having now searched for hours I finally found the answer on another forum and I thought I would share it in here.

Basically the solution is a new driver, but to be allowed to install a new driver we need to modify the .inf file first.

This worked with my iMac 27" - Ati HD 4850:
VERY step-by-step... sorry

- Download the desired driver ( I use the driver from this post 8.723).
- Start the very first install, it will unpack into the selected folder.
- Then after it having unpacked, cancel the installation.

- Locate the folder with the .Inf files ( eg. C:\ATI\Support\10-4 vista64_win7_64_ddPackagesDriversDisplayW76AINF )
- Open any of the 2 .inf files (doesn't matter which) in notepad.
- Replace the lines which contains the name "ATI Radeon HD 4850"
So that it equals = ati2mtag_R7X, PCI\VEN 1002&DEV_944A&SUBSYS00B5106B
Like so
*"ATI Radeon HD 4850" = ati2mtag_R7X, PCI\VEN 1002&DEV_944A&SUBSYS00B5106B*
- Save the file.

- Open device manager, selected the Ati-card, press update driver...
Select "Locate and install driver software manually"
Select "Let me pick from a list..."
Select "Have disk..." and navigate to the folder with the modified .inf file.
Choose "ATI Mobility Radeon HD 4850 Version whatever "
It will warn you that the driver is unsafe - ignore this.
If you are as lucky as I, your driver should now be installing...

Hope this might help someone

mbatte

Level 1

0 points

Oct 12, 2010 1:08 PM in response to Buhu

Just to confirm, when I install the ATI Catalyst package, it will only install and update the drivers and it does NOT install ATI Catalyst application. I remember for my PC I use to get an ATI icon at the bottom of the desktop that I could open up to check out the drivers, video card setting, etc. However, it seems that in Bootcamp, it does not allow it to install.

Is that correct? or is is that the ATI Catalyst no longer installs this application, and is for the drivers only.

Jan 6, 2011 7:46 AM in response to MacChris

This same thing is happening with my MBP 17" Core Duo (Non-Unibody). All of these instructions/problems/drivers seem to be affecting people with iMacs... Anyone have this issue with a machine like mine? Obviously the drivers would be completely different...

27in iMac (late 2009) ATI 4850 drivers problem in Windows 7