[altis]

I think it's all to do with CRT vs LCD technology.

With a CRT the speed of the dot on the screen is defined by the graphics card so that the faster the refresh rate the better the picture looks.

With an LCD I think the signal has to go first into a dual-port RAM. Then it is read out in rows to the screen at a rate defined by the controller card in the monitor. Thus the actual refresh rate is not the same as that provided by the graphics card. Indeed, the faster the graphics card is pumping it out the less time the dual-port RAM will have for the screen side. I don't know this for sure but it must be something like that.

Oh, it's late and I'm not making much sense ... but you'll probably understand anyway!