To this day, Crysis continues to tax the latest GPUs and will probably do so for the next year. While default frequencies are pretty darn fast, pushing the frequencies a little more fills in the performance gap between it and the stock clocked ZOTAC GTX 275 Video Card.
Farcry 2 comes with a handy built in demo that'll run three tests at your chosen resolution. It's nice when games offer that feature just so you can compare your own video cards and to figure out if your hard earned money was worth the upgrade. Naturally, the GTX 260 makes good use of the extra frequencies despite the game's expansive mapping and detailed worlds.
World at War
World at War is one seriously dynamic game. Every time I think that the 90 plus frame rates are going to hold, the intense fighting sequences stress any graphics card especially at higher resolutions. At any rate, 40+ frames per second is certainly playable and that ENGTX260 Matrix is more than capable.
Left 4 Dead
We must include the occassional older game engine for some realistic comparisons. Not to mention, this is one heckuva fun game to play. In Left 4 Dead, the size of the maps and sheer numbers of attacking zombies can keep the frame rates from topping 100. If you're playing this one, make sure you max the graphics to see all the eye candy.
Here's one game title that tests a lot more than just textures and mapping. It puts a lot more of the dynamic lighting to work as well. In either case, it's interesting to see great mapping and physics at work. It's interesting to note that the ENGTX260 at its overclocked settings provides the jump on its bigger brother, the GTX275.