iota Posted April 6, 2006 Share Posted April 6, 2006 I verified that this isn't a computer problem -- a screenshot of the XP desktop looks fine when viewed under OS X. However, while in XP, the screen has a grainy look to it -- as if the entire screen is a compressed jpeg image. Even areas of solid color (desktop background, gray areas inside of programs) have a slightly randomly dithered look. This only happen AFTER installing the ATI drivers, as far as I can tell. I tried flipping some DVI options on and off in the ATI display control panel but no change. Also happens no matter what the resolution, and even in games like Doom 3 -- however, wasn't happening during the windows install or until the ATI drivers were installed. I tried both 16bit and 32bit color modes, too. Is anyone else seeing this problem? 17" iMac here. Link to comment Share on other sites More sharing options...
dopefish3d Posted April 7, 2006 Share Posted April 7, 2006 I am seeing the same thing on my MBP as well. Link to comment Share on other sites More sharing options...
bimboles Posted April 7, 2006 Share Posted April 7, 2006 I find the screen on the MBP is too bright but when your drop it down a notch it is too dull. I also find that on full brightness the screen seems to flicker a bit. Link to comment Share on other sites More sharing options...
geepee Posted April 7, 2006 Share Posted April 7, 2006 I noticed the exact same thing, and got my friend who was here to see if he could see it also just so I knew I wasn't crazy, and he could see it also. It's kind of annoying, but I don't notice it when I'm playing a game. Link to comment Share on other sites More sharing options...
BitterSweet Posted April 7, 2006 Share Posted April 7, 2006 Not noticing anything here on my iMac 17" 1.83/512/160, image is lovely and clear. Link to comment Share on other sites More sharing options...
VaiOSX Posted April 7, 2006 Share Posted April 7, 2006 Check in your video setting's advanced tab if your refresh rate is not set to 60hz. Link to comment Share on other sites More sharing options...
iota Posted April 7, 2006 Author Share Posted April 7, 2006 Check in your video setting's advanced tab if your refresh rate is not set to 60hz. Video is set at 60hz for me. At least I'm not the only one; maybe there were some iMacs with a batch of bad video cards? This looks like digital noise (loose internal connection or something), but doesn't appear while in OS X. Link to comment Share on other sites More sharing options...
geepee Posted April 7, 2006 Share Posted April 7, 2006 Video is set at 60hz for me. At least I'm not the only one; maybe there were some iMacs with a batch of bad video cards? This looks like digital noise (loose internal connection or something), but doesn't appear while in OS X. Yeah, mine is at 60hz also. Changed it to 75 and 85 just to see and it did nothing. Mine also doesn't do this in OSX. I tried installing the Omega drivers to see if that would make any difference, and it didn't. What we're seeing kind of looks like a thin layer of dust all over the screen which doesn't move when things on the screen move. If you scroll down on a webpage, the "dust" stays put while the image below it moves. It doesn't seem visible on light colors, only darker colors. It's especially not visible on white, but its totally visible on the default blue background if you switch to the Windows Classic theme instead of the WindowsXP default theme. Link to comment Share on other sites More sharing options...
iota Posted April 8, 2006 Author Share Posted April 8, 2006 Yeah, mine is at 60hz also. Changed it to 75 and 85 just to see and it did nothing. Mine also doesn't do this in OSX. I tried installing the Omega drivers to see if that would make any difference, and it didn't. What we're seeing kind of looks like a thin layer of dust all over the screen which doesn't move when things on the screen move. If you scroll down on a webpage, the "dust" stays put while the image below it moves. It doesn't seem visible on light colors, only darker colors. It's especially not visible on white, but its totally visible on the default blue background if you switch to the Windows Classic theme instead of the WindowsXP default theme. yes, that is exactly the problem that I am having -- using the classic theme makes it worse. I cleaned the screen off at first thinking that it was dust. adjusting the brightness doesn't help, and no settings inside the display control panel seem to help either Link to comment Share on other sites More sharing options...
ralleria Posted April 8, 2006 Share Posted April 8, 2006 I have the same problem on my MacBook, it looks like a monitor problem in my opinion. On OS X is less annoying because everything concerning the GUI is bigger...in xp is much more enphasized. I don't know what to do whether calling the customer service or not.....I don't wanna wait 2 weeks in order to have the same problem with a different monitor or a different videocard P.S. I don't know about iMacs but every MacBook I had (3) and I've seen has this problem Link to comment Share on other sites More sharing options...
geepee Posted April 8, 2006 Share Posted April 8, 2006 I have the same problem on my MacBook, it looks like a monitor problem in my opinion.On OS X is less annoying because everything concerning the GUI is bigger...in xp is much more enphasized. I don't know what to do whether calling the customer service or not.....I don't wanna wait 2 weeks in order to have the same problem with a different monitor or a different videocard P.S. I don't know about iMacs but every MacBook I had (3) and I've seen has this problem I've tried and tried to replicate this issue in OSX and have yet to do so. The first time I booted into WinXP, I noticed it. I've had my iMac for a couple months now and have never seen this before. Link to comment Share on other sites More sharing options...
imapetert Posted April 9, 2006 Share Posted April 9, 2006 I have the same problem on my MBP as well ... but I am gonna say something odd. I kinda like it in my games. It gives Half Life 2 an extra layer of gritty that really makes it look good, at least to me. Link to comment Share on other sites More sharing options...
ralleria Posted April 9, 2006 Share Posted April 9, 2006 I've tried and tried to replicate this issue in OSX and have yet to do so. The first time I booted into WinXP, I noticed it. I've had my iMac for a couple months now and have never seen this before. I was talking about the MacBooks, don't know about iMacs maybe there it's just a driver problem Link to comment Share on other sites More sharing options...
SilverDragon Posted April 9, 2006 Share Posted April 9, 2006 I can confirm I see the same on my iMac, the grainyness is present in OS X too, though it is very hard to spot, but I did notice it a bit when i first booted up, compared to my previous lcd panel, though under OS X its so slight that most probably woldnt notice it. under xp it was very very noticable though with the ati drivers, flat desktop looked like it was make up of 3-4 close colours in weird grainy pattern. I expect its something that could be alleviated to OS X levels by either driver/output tweaking, or update. heres hoping it comes soon though. Link to comment Share on other sites More sharing options...
iota Posted April 17, 2006 Author Share Posted April 17, 2006 Has anyone else had this issue? Any fixes or updates? Link to comment Share on other sites More sharing options...
Muriac Posted April 21, 2006 Share Posted April 21, 2006 Ok, here's the deal: the graininess is dithering produced by the graphics card outputting a 24-bit picture with only 16 bits of colour. This is why there is no difference between 16- and 24-bit colour in XP on Intel Macs. The question is why this is happening. We know it's not a driver issue, because people have used Omega drivers and nothing has changed. We know it's not a hardware issue, because it doesn't happen in Mac OS. To people saying it does but only faintly, what you're seeing is the slight variation in pixel brightnesses apparent on every LCD. That's not the same thing. Proof is that the issue is not apparent when running XP under Parallels. There's nothing wrong with the OS X video pathway, but there is something wrong on the native XP side. My current theory is that the issue lies not in the regular drivers, but in a compatibility layer which Apple installs alongside the standard Catalyst driver that the Boot Camp CD provides. This layer remains when you install the Omega drivers. I think something is happening in this layer that forces a 16-bit output no matter what. I have no idea what to do about it, but I'm posting everywhere people might be able to help: Apple Support Forums, Ars Technica, XP on Mac, and Driver Heaven. The only positive thing I've heard is that turning off Powerplay might reduce the noise. I don't have any idea why that would be. As far as I know, modern graphics cards take little or no performance hit when using 24 or 32 bit colour instead of 16 bit. Thus, they probably don't consume any less power when using 16-bit colour. Oh, and everyone should email Apple's Boot Camp feedback address. Link to comment Share on other sites More sharing options...
non sequitur Posted April 21, 2006 Share Posted April 21, 2006 Ok, here's the deal: the graininess is dithering produced by the graphics card outputting a 24-bit picture with only 16 bits of colour. This is why there is no difference between 16- and 24-bit colour in XP on Intel Macs. The question is why this is happening. We know it's not a driver issue, because people have used Omega drivers and nothing has changed. We know it's not a hardware issue, because it doesn't happen in Mac OS. To people saying it does but only faintly, what you're seeing is the slight variation in pixel brightnesses apparent on every LCD. That's not the same thing. Proof is that the issue is not apparent when running XP under Parallels. There's nothing wrong with the OS X video pathway, but there is something wrong on the native XP side. My current theory is that the issue lies not in the regular drivers, but in a compatibility layer which Apple installs alongside the standard Catalyst driver that the Boot Camp CD provides. This layer remains when you install the Omega drivers. I think something is happening in this layer that forces a 16-bit output no matter what. I have no idea what to do about it, but I'm posting everywhere people might be able to help: Apple Support Forums, Ars Technica, XP on Mac, and Driver Heaven. The only positive thing I've heard is that turning off Powerplay might reduce the noise. I don't have any idea why that would be. As far as I know, modern graphics cards take little or no performance hit when using 24 or 32 bit colour instead of 16 bit. Thus, they probably don't consume any less power when using 16-bit colour. Oh, and everyone should email Apple's Boot Camp feedback address. dude, keep us updated. thats the only complaint i have about bootcamp. Link to comment Share on other sites More sharing options...
leadhead Posted May 11, 2006 Share Posted May 11, 2006 Any other progress on this? Link to comment Share on other sites More sharing options...
Chrysaor Posted May 11, 2006 Share Posted May 11, 2006 This is weird. OSx86 is having similar 16-bit color depth issue with digital connections. If you have a digitally connected monitor or a laptop, you get 16-bit color depth in OS X. (it is fine with analog) Link to comment Share on other sites More sharing options...
Swad Posted May 15, 2006 Share Posted May 15, 2006 Muriac- Do you think there would be anyway of "forcing" the Mac to take the color the way it's supposed to? Surely with as many driver geeks as we have around here someone could figure out a quick hack. Link to comment Share on other sites More sharing options...
arturv Posted May 15, 2006 Share Posted May 15, 2006 I attached the image that demonstrates the problem. Interesting to note that on dual monitor setup there is no dithering on secondary screen. So video card and drivers under Windows are quite capable to deliver true colors. It almost seems like LCD screen needs proper drivers. I suspect, that it happens during windows booting since thats when video is set to 16bit first (during Windows Logo) and for some reason it doesnt come out of it. Link to comment Share on other sites More sharing options...
Muriac Posted May 16, 2006 Share Posted May 16, 2006 I've found a little more information on the topic. From a Video Developer Note at Apple: The 17-inch model supports an LCD display size of 1440x900 pixels at 100 dpi. The graphics card temporally dithers the 6 bits per component to show up to millions of colors. The 20-inch model supports an LCD display size 1680x1050 pixels at 98 dpi and supports 8 bits per component to show up to millions of colors. This explains why the dithering looks better than 16-bit colour, but worse than 24-bit: it's actually 18-bit. Presumably this is also why the problem doesn't occur in the 20" iMacs. OS X's driver must be doing some random dithering which is different every frame, whereas the XP driver does the same dithering every frame. Muriac- Do you think there would be anyway of "forcing" the Mac to take the color the way it's supposed to? Surely with as many driver geeks as we have around here someone could figure out a quick hack. Yeah, that's what I thought. And with so many people running Boot Camp on their MBPs and 17" iMacs, there's certainly plenty of demand. I spoke briefly with the Omega Driver dev, but he said the only people who could help me probably work at ATI. I don't know how to go about asking ATI, and I have a feeling they wouldn't be very responsive anyway. Perhaps someone here could take a crack at it? Link to comment Share on other sites More sharing options...
Severnya Posted May 16, 2006 Share Posted May 16, 2006 Turn on ClearType in the display options. I get a similar effect on my PC laptop. Just a hint. Rich Link to comment Share on other sites More sharing options...
Muriac Posted May 17, 2006 Share Posted May 17, 2006 I'm not seeing any difference. What would ClearType have to do with display depth? Link to comment Share on other sites More sharing options...
Severnya Posted May 19, 2006 Share Posted May 19, 2006 nothing it alters how fonts are rendered Link to comment Share on other sites More sharing options...
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