Weird dots when previewing videos

[churchtech007]

I have a iMac running 6.8 with the latest updates. Recently I started getting these weird dots (see pictures) when opening properties in ProPresenter. I originally thought this was just a PP issues but now I get them when I preview them with finder.
You can see on one of the pictures that the videos were made a year apart and both get the dots. This problem started a couple months ago but seems to be getting worse and will lock up the computer sometimes.
Is my GPU going bad?

Thanks!

[petereit]

What model iMac? This looks like what I saw before my imac's logic board kicked the bucket. But that was an old pre-intel iMac with bad capacitors.

Check the air inlet ports along the bottom edge of the monitor to ensure theyre not plugged with dust. If they are, vacuum them clean then spray liberally the with canned air while you vacuum the top exhaust slot.

[churchtech007]

It's a newer mac, just past the 1 year warranty.

Thanks for the air tip, I'll try it.

[Morshu]

You can use iStat to monitor some of your Mac's temps. I'm not sure if it monitors GPU temps specifically, though. Just see if any are abnormally high. You could also try running Apple Hardware Test (http://support.apple.com/kb/HT1509)
Good luck!

[churchtech007]

Temp's are good and the hardware check came back with no problems.
Mark, I blew it out but it really wasn't that dirty and it definitely was clogged.

The weird thing it's only in preview. If I just play the videos in QT or PP they play fine. But try to preview them in finder (or in PP) and it goes wacky.

Could PP be causing a conflict even if it's closed? Should I uninstall PP and see what happens?

[EricE]

There is a thread about this on the renewed vision forums - I can't remember if there was a resolution to it or not - you might want to head over there and search around for it...