Intel Imac screen becomes pixilated - help!

[yvettek]

I have my Imac (Intel Core Duo2) for just over a year now.
A couple of weeks ago I began to experience a problem - My screen becomes pixilated from time to time. It is beginning to happen more frequently. It disappears when I take a desktop icon and drag it around the screen.
It mainly happens when I first startup the mac and sometimes it appears when it is shutting down. I'm not sure if it is affecting anything, just a bit worried.
Anyone any ideas what the problem could be?
Thanx

 

[johto]

I have my Imac (Intel Core Duo2) for just over a year now.
A couple of weeks ago I began to experience a problem - My screen becomes pixilated from time to time. It is beginning to happen more frequently. It disappears when I take a desktop icon and drag it around the screen.
It mainly happens when I first startup the mac and sometimes it appears when it is shutting down. I'm not sure if it is affecting anything, just a bit worried.
Anyone any ideas what the problem could be?
Thanx

Something wrong with the hardware. Logic board or the GPU perhaps? I would get it replaced / checked if under warranty.