Mac Screen refreshing

Does your Mac screen go black, refresh, go black again, refresh again every few minutes? This is something I have noticed over the last year or two with Macs, so I'm not sure which iteration of OSX it started with. Happens with my desktop and laptop machine. What is this, why does it do it, can it be 'turned off'. I find it quite irritating when one is working on something or reading something, to wait those few seconds every few minutes while the screen does it's thing.

I don't have anything that looks like that but I have had screen refresh problems with my Mac Pro. Turns out that the video card overheats. I replaced the ATI card with an nVidia but that one fails the same way. I also noticed it with my first G5 tower. My new displayport-to-dualDVI adapter freaks out frequently in a very similar way.

I wonder if the notebook and desktop are failing in different ways?

I have smc fan control; I'll play with minimum fan speeds and see if that makes any difference.

I've never had my Mac screen go black. Does it turn off completely? It's not an energy saver thing?

It's as if one were turning the screen off briefly, say 3-4 seconds, then comes on 2-3 seconds, then off again 3-4 seconds, then comes on again and stays on. (My Eizo monitor actually beeps like it does when turned off) I've checked the energy saver in preferences, and that's not the issue. It does it on my laptop as well, but usually just goes black once.

I had a graphics card problem a year so ago which was crashing the computer on my MacPro - Apple replaced it free of charge and I've had no more freezes / crashes since.

I've just tried increasing minimum PCI fan speed from 500-750rpm using smc fan control, and so far it seems like that may have worked, so it may be something to do with overheating of the graphics card. I have not tried the laptop yet.

I would test your problem with a different monitor connected to your MacPro.

(maybe the monitor's power supply is dying.)

I've never had my monitor fade in and out on my MacPro (early 2008 w/nVidia 8800GT); this includes running very intense 3D graphics for long periods of time.

Take Care,

ChrisS

I would test your problem with a different monitor connected to your MacPro.

(maybe the monitor's power supply is dying.)

 

I've never had my monitor fade in and out on my MacPro (early 2008 w/nVidia 8800GT); this includes running very intense 3D graphics for long periods of time.

 

Take Care,

ChrisS

I will try some different options, but I don't think it's the monitor - I have 2 monitors, the Eizo and Apple and they both go out at the same time if they are both running I have the ATI Radeon 1900 card. Also happens, though less frequently with my laptop. I do keep my laptop in one of those plastic protective cases so I guess that could make it run warmer. So far since I increased the base fan speed it has not happened again, but we'll see.