iMac - Very Grainy Display

wormitian · wormitian #1 (**permalink**)

02-16-2009, 09:06 AM

My old iMac running OSX 10.4.1 has suddenly decided to make the display very "grainy" and I am wondering if this is a problem with the OS or the hardware.

I tried altering the brightness and contrast but no good.

When I boot up the pc it looks fine until the wallpaper appears when it is ok for a second or two and then jumps to the grainy display.

Anyone any ideas.

Thanks.

Chilbear · Chilbear #2 (**permalink**)

02-16-2009, 09:46 AM

Update your OS to a later version as the early ones were suspect. Get the latest Combo updater and try that first.

Sounds like a bad driver as a first guess. What kind of plug is the monitor using - DVI or other? Maybe the video card is going away (overheating?) and defaulting to a lower res. Also go into the Preferences>Displays and make sure what you have for a monitor is correctly identified by the system and it should allow a choice of resolutions in the pull down.

kahlil88 · kahlil88 #3 (**permalink**)

02-16-2009, 10:50 AM

Check out your display preferences - make sure it's set to millions of colors instead of thousands, as this will make the picture appear "grainy"

pigoo3 · pigoo3 #4 (**permalink**)

02-16-2009, 01:43 PM

Quote:

Originally Posted by kahlil88

Check out your display preferences - make sure it's set to millions of colors instead of thousands, as this will make the picture appear "grainy"

Excellent suggestion! I bet this is the problem. The OP's computer is probably set on 256 colors...instead of thousands or millions.

- Nick

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iMac - Very Grainy Display

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wormitian #1 (permalink)
Member Since: Feb 16, 2009 Posts: 1	02-16-2009, 09:06 AM My old iMac running OSX 10.4.1 has suddenly decided to make the display very "grainy" and I am wondering if this is a problem with the OS or the hardware. I tried altering the brightness and contrast but no good. When I boot up the pc it looks fine until the wallpaper appears when it is ok for a second or two and then jumps to the grainy display. Anyone any ideas. Thanks.
	QUOTE Thanks

Chilbear #2 (permalink)
Member Since: Jun 14, 2007 Location: Toronto Posts: 574 Mac Specs: 2xiMac24 w Parallels 6 (1x White, 1x Aluminum), iPhone 3GS with iOS5	02-16-2009, 09:46 AM Update your OS to a later version as the early ones were suspect. Get the latest Combo updater and try that first. Sounds like a bad driver as a first guess. What kind of plug is the monitor using - DVI or other? Maybe the video card is going away (overheating?) and defaulting to a lower res. Also go into the Preferences>Displays and make sure what you have for a monitor is correctly identified by the system and it should allow a choice of resolutions in the pull down.
	QUOTE Thanks

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