Artifacts not caused by video card?

[imported_MadHatter]

I have a Samsung 152T and I've used it with three different copmuters. I used it with four different video cards: nvidia 5700 nu, nvidia 6800GT, Radeon xpress igp, and a 7800GTX.

I never noticed anything with the 5700 or 6800GT but recently while playing Rise of Nations I noticed what looked like artifacting occasionally on the Radeon igp. It was very rare and I only noticed it once. When I got my new system I noticed it again, this time while playing Doom 3 and Rise of Nations. It only happened once in both games for a split second.

It's hard to describe what it looks like. It looks like a really narrow (maybe a cetimeter or so at it's base) orangish triangle that stretched from the top of the monitor to the bottom. What could be causing this? I'm certain it's not the graphics cards so could it be the cable?

Edit
I'll be trying it on a X600XT this weekend so I'll see if I notice anything on it.

 

[hans030390]

if i'm correct, can having a bad psu cause cards to do this? or one that doesnt have enough power?

 

[Matthias99]

Could be the monitor or cable, or a flaky power supply (unlikely, but possible, I guess; bad/insufficient power can cause almost anything to happen).