Strange LCD problem

Last weekend I bought a Viewsonic VP201s and I've run into a strange
problem with it. When I increase the contrast levels, gray objects
start turning pinkish in the higher range. I thought there was
something wrong with it, took it back and got it exchanged, but it
does the same thing with the new one (though not as bad). I'm now
wondering if it might be my video card, an ATI 9800. The monitor is
hooked up via the DVI output.

Another issue, certainly not related to the video card is that the
monitor buzzes when the brightness is turned down.