...continuous strain on a graphics card!!! Try 3DMark2005 or download some of the new or slightly older demos available for PC games, for e.g FarCry, Doom 3, Fear demo, Quake 4 perhaps, or Hl2. Any of these games are fairly taxing on the graphics sub-system, albeit some more than others. But what exactly are you trying to achieve, you wanna see FPS or what? Oh...Aquamark is a very good indication of real life playability of your GC. A little more info please, on what it is you want to measure
my aim is like to get to know ow long my gfx card will last under stress and i got hl2 and fear demos but i am not gin to always play the same demo unless it is bf2 demo