I've got a strange problem with my Mac Mini and MOS, for some reason when I have dark wallpapers on Ambient I get lots of dancing/flickering green pixels all over the top-left centre section. I can highlight the mouse over them and they vanish, they also don't appear on any other screens apart from ambient, and if I move a window over it the window is not affected.

It only seems to be dark colours that are affected too, I don't think it's GPU based as it also shows on screenshots, as you can see from the attached grab. Any ideas? It's rather distracting to say the least!

http://i.imgur.com/AVYvK.jpg

(look at the left of the screen above the centre)

Sounds weird. I would say it is memory corruption.

You could try running LCD Monitor Test (it is part of the MorphOS install). Maybe it appears there too?


[ Edited by itix 11.04.2011 - 21:59 ]

the LCD monitor test is fine, however googling for Mac Green Pixels shows heaps of results... Seems it could be an Apple hardware issue, odd it only appears on Ambient and not in any programs though!

Probraly a heat-issue and since Ambient maybe the only screen running in 3D (aka enhanced layers) it seems plausible.

Might be a good idea to open the Mini and check for dust-bunnies and suchlike.

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[ Edited by Velcro_SP 31.08.2011 - 08:48 ]

> I'd suspect you won't get rid of that without changing out the card.

In a Mac mini there's no 'card' that could be changed.

To me this does not look like a hardware issue at all: more like a memtrash caused by some application you're running. See if this happens on a direct MorphOS Boot-CD boot with just this wallpaper added - my bet is that it won't.

Thanks for the tips guys.

I've tried your advice Jacadcaps, same issue when booting from the CD.

Also tried cleaning out the internals of the Mac Mini, problem still remains.

I've noticed it sometimes doesn't appear until a couple of min after boot, leads me to think it might be heat related.

Reading Apple forums, it seems the problem was quite common with PPC macs, but nobody seemed to have an answer apart from "get it replaced by Apple", not much
good these days though :/

I had big trouble making my mini to work with my 1680x1050 LCD. I had a lot of flickering green pixels. Reducing the GPU memory frequency solved the issue.

Tcheko - I'm also trying to run 1680x1050 on an LCD and having the same issue!

I'm new to MOS really, how do you reduce the GPU mem frequency? I'm very keen to solve this annoying issue!

It seems this is something I'd need to do in OpenFirmware? If so can anyone help me on underclocking the radeon 9200 on my mini g4?