strange visual disturbance when veiwing grey scale images!

This is weird but on certain games and when view grey scale images i get this strange effect on the pixels!.

Is my Graphics card on its way out?

On the attached picture i've zoomed into a greyscale photo to show the effect better.

anyone know whats causing it.

cheers

ps that veriticle line of pixels twinkles but when zoomed out it appears all over the image on certain shades of grey only

 

Are the colors set to 32 bit High at the resolution settings?

 

Hi, it is.


I've just upgraded my graphics card to a gtx260 ,now i've only got a 520watt power supply, i was wondering whether that could be a problem for it.