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Win7 on iMac: Strange moiré like effects on display

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CrazyLexx

macrumors newbie
Original poster
May 31, 2009
22
0
Hi folks,

i'm currently using a 64-bit version of Windows 7 RC on an 21" iMac. But I've noticed that the display has a strange moiré-like effect (picture looks "instable", like the surface of disturbed water), that is not present under MacOS 10.5. Any ideas what i causing the iMac display to look so different when running Windows? Is there a dedicated iMac display driver for this hardware that might change this?

Thanks,
TOM
 
Bill Gates

Bill Gates

macrumors 68030
Jun 21, 2006
2,500
14
127.0.0.1
It very well could be a driver issue. What graphics processor does your iMac have, and what driver version are you using?
 
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CrazyLexx

macrumors newbie
Original poster
May 31, 2009
22
0
My iMac uses an ATI Radeon HD 2400 with the latest ATI beta 64-bit drivers. But I've also noticed that the build in monitor is just listed as a default plug & play monitor. Maybe those drivers don't use the proper refresh rate settings?
 
Bill Gates

Bill Gates

macrumors 68030
Jun 21, 2006
2,500
14
127.0.0.1
The fact that the monitor is listed as such is not an issue. However, I think it may be worth a shot to try other drivers. Unfortunately I'm no expert at troubleshooting issues like this so I'm at a loss if this doesn't help you. Try using drivers from here. I took most of the default settings that are used when the driver is installed out of Apple's non-functioning driver shipped on the restore discs of the new iMac.
 
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CrazyLexx

macrumors newbie
Original poster
May 31, 2009
22
0
Thanks, gonna give your modified ATI drivers a try and let you know if those do the trick.

However, I'm still curious to know if this problem only happens on my system. The distortion effect can be best seen on white areas like a blank Word document.
 
L

LOLaMac

macrumors regular
Jun 2, 2009
109
0
Hey there, you are most certainly not alone on this.

I have been seeing the same thing and it's driving me up the wall (I have a 20" 2.4 iMac with the Radeon 2600HD). It's a vertical pattern that appears across certain colors and is very distracting when you know it's there. And it is not a static pattern either; if you look closely at it and pick out one of the "lines" you can follow it and see they're moving across the screen from right to left, in a wave.

I downloaded the Win7 catalyst drivers (Radeon Mobility 2600) and when I fool around with the control center display settings for brightness/contrast/gamma, funky things happen. As I alter the settings, the colors that were "wavy" become solid while other colors that were solid are now wavy while yet other colors get horizontal lines through them, looking much like scan lines. As well, certain colors that are gradients, such as an image that goes from light grey to dark grey, will go from being a smooth gradient, to having bands; the effect is akin to playing a game in 16bit color as opposed to 32bit color (if you can picture that, or even understand wht I mean).

The problem doesn't exist under OS X, the colors are beautiful and as flawless as can be, but under Windows 7....yikes. I wish there were a fix for this.
 
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CrazyLexx

macrumors newbie
Original poster
May 31, 2009
22
0
Just wanna let you guys know that I've upgraded my display driver to version 9.5beta which can be found over at the ATI side but this strange wave like effects are still present. :-(

But I've to change by description above: The effect can be best seen in the blue/gray tab area of Internet Explorer 8.
 
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CrazyLexx

macrumors newbie
Original poster
May 31, 2009
22
0
Ok, still playing around with those drivers and I've come up with a strange observation:

When I install the newest drivers, the screen goes black for a second before the install routine is done and after that the moiré distortion is completely gone - but just to come back the moment I restart the system or logon to a different user. :mad:
 
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CrazyLexx

macrumors newbie
Original poster
May 31, 2009
22
0
No guesses why the distortions are gone directly after the ATI drivers have been installed and why the come back after a system reboot?
 
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CrazyLexx

macrumors newbie
Original poster
May 31, 2009
22
0
Just update to the new 9.6 driver version over at Bill Gate's thread but those moving lines are still there. :mad:
 
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UnInvincible

macrumors member
Jan 30, 2008
35
0
I don't think it's a driver issue, I have a few video problems in windows xp, including faint vertical lines best seen in certain colors, similar to your problem I guess. I've tried a thousand different drivers and nothing ever changed it. You can see my other weird problem by checking out my other posts. I personally think it's a system file or something that isn't working correctly for some reason. I have the 2.4 GHz HD 2600xt running Windows xp 32 bit, fyi.
I've given up trying to fix my problems, besides installing newer drivers when they're released and praying, but if you find a solution to your problem make sure to tell us.
 
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UnInvincible

macrumors member
Jan 30, 2008
35
0
Hmm... I don't think my display has ever looked better right after installing drivers, so we could be having different issues. Have you tried using the Mobility Modifier on the latest Catalyst drivers? If you don't know what that is it's a program that modifies the ATI Catalyst drivers to work for laptop cards, and since that's what's in the iMacs it's required in order to use the Catalyst drivers I believe, but from your previous post it says you have the latest 64 bit Beta drivers... did those work right after you downloaded them or did you modify them with the Mobility Modifier and not mention it?
 
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CrazyLexx

macrumors newbie
Original poster
May 31, 2009
22
0
Maserati7200 said:
Those don't exist :D
Click to expand...
Right, typo on my part.

UnInvincible said:
Hmm... I don't think my display has ever looked better right after installing drivers, so we could be having different issues. Have you tried using the Mobility Modifier on the latest Catalyst drivers? If you don't know what that is it's a program that modifies the ATI Catalyst drivers to work for laptop cards, and since that's what's in the iMacs it's required in order to use the Catalyst drivers I believe, but from your previous post it says you have the latest 64 bit Beta drivers... did those work right after you downloaded them or did you modify them with the Mobility Modifier and not mention it?
Click to expand...
That's strange, since I was able to install the regular Catalyst drivers on my system without having to modify them...

http://game.amd.com/us-en/drivers_catalyst.aspx?p=win7/windows-7-64bit

Also, I've seen someboy mention some kind of popular tweaking tool for ATI cards but can't remember the name. Maybe that program has some options I should try...?!
 
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UnInvincible

macrumors member
Jan 30, 2008
35
0
Are you sure it actually installed the drivers? That program they use installs some things but if it doesn't detect your hardware then it doesn't install the display drivers. I had to use the mobility modifier in order for it to install the display drivers.

And I think the tool you are thinking of is ATI Tray tools.

I just recently changed from Windows XP to Windows 7 64-bit, and unfortunately I am still having all my previous display issues with the current drivers, so now I'm thinking it could be a hardware issue, although the fact that it doesn't happen in Mac OS X is strange. Maybe it has to do with the firmware or something... because I noticed these lines as soon as I was installing Windows 7.
 
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CrazyLexx

macrumors newbie
Original poster
May 31, 2009
22
0
Ok, just installed the new final version of the ATI drivers and those waves are still running down my screen. :mad: I'm seriously considering to buy a dedicated all-in-one Windows machine to run Windows 7 on it as this iMac (and Apples support for it) just doesn't get the job done.
 
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CrazyLexx

macrumors newbie
Original poster
May 31, 2009
22
0
Any news on this one yet? Maybe those bc 3.0 driver can finally fix this problem?
 
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CrazyLexx

macrumors newbie
Original poster
May 31, 2009
22
0
Maybe we can somehow can this problem fixed by manually trying new drivers?

Does anyone know how I can find out which kind of Intel chipset is used in my iMac? Maybe there's a better or newer one out from Intel...
 
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CrazyLexx

macrumors newbie
Original poster
May 31, 2009
22
0
Anyone? This is driving me (and my eyes :eek:) crazy every time I boot up the machine. Since those lines disappear after I install a new graphic card driver, there shoud be a way to fix this somehow.
 
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Chris.

macrumors regular
Aug 22, 2008
124
1
UK
Have had the same problem with my iMac since getting it in August 2008. Windows Vista & 7, still not solved :(.
 
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CrazyLexx

macrumors newbie
Original poster
May 31, 2009
22
0
Just to get this thread back up and keep you posted:

Tried the new 9.9 catalyst drivers from ATI (which update the drivers to version 8.65) still doesn't do it.

It really drives me mad, because right after the new drivers are installed and the screen goes black for a moment, all those strange distortions are gone and it shows me just how clean and calm Windows 7 could look on my iMac if only for those bad drivers we get from Apple! Reboot the machine or change the user and those wavy lines are back as usual.

Maybe someone could get at it and join me in finding the cause for this. Is it just some strange display setting (refesh rate) or a problem withthe mainboard drivers?
 
rgarjr

rgarjr

macrumors 604
Apr 2, 2009
6,820
1,050
Southern California
I have W7 64-Bit on my MacBook and I have the waves going down on my screen. They are really noticeable when you have a grey window on there.

UPDATE:

I just rolled back the graphics drivers and it solved the problem on my laptop. I had the latest 11/20/09 driver from NVIDIA, and rolled it back to the 8/19/09 driver.
 
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