Strange faint horizontal lines on my monitor in BF

I see strange horizontal lines on my monitor when a game is running. They're clearer when it's dark on the screen and for some reason, they show up very clearly when I'm in a tank on either BF game. I thought I'd post it here, in case any other BF players have managed to notice the same thing when they're in a tank.

I've seen a few people mention something like this on other forums, but I'm unsure if it's the same issue, as I've tried all the troubleshooting tips I found and it still remains.

I recorded a short clip of it, to make it easier: http://www.youtube.com/watch?v=VPMiNInc7Co

It's best if you put it at the highest quality and full screen to be able to see them. I focus on a single point and you can see them "flickering" slightly.

At first I thought it was my graphics card. I changed from my 7950 back to my 6950, and the issue still remains. I also tried two different VGA cables with 2 different DVI adapters, as well as using the HDMI from my card to my LCD TV, and the issue showed on that as well. 

I have a mate that said it was interference and to get a HDMI to VGA adapter, but I clicked that it still occurred with my HDMI TV, so that can't be the cause. The lines don't "interfere" with gameplay, but they're bloody annoying being there all the time. 

Thanks

Damien