http://www.pcper.com/article.php?aid=1034

From the article:

An interesting addition to the GTX 580 hardware is a hardware-based current monitor that keeps track of the voltage and current coming IN through the 12V rails on the 8-pin, 6-pin and PCIe bus. The goal here was to keep the GPU within the power specifications shown above in all cases, even when programs like the oft-despised FurMark are run that heat up the GPU "more than any real-world application ever could" according to NVIDIA. The logic on board will adjust the clocks and performance of the GPU when these types of current draws are detected thus limiting the benefit of such applications for temperature and cooling testing.

While I have no problem with NVIDIA protecting their hardware in this way I am curious to see how long it will take for a "real-world" application to hit this current draw limits in some way and initiate these performance drops on its own. FurMark doesn't really do anything special to the GPU - it simply attempts to work as much of the GPU core as possible all at one time. In many people's view, this is only testing the top efficiency possible out of the GPU - something that software developers should really be striving for anyway.
Yikes! Nvidia has hit a new low. I try to stay manufacturer agnostic when it comes to the Nvidia vs. AMD fight, but here is a "feature" installed for two evil purposes: to trick benchmark utilities and to stop overclocking and watercooling of their cards. I mean they went out and actually allocated ICs and card real estate for this rubbish. I know that corporations are evil, but this is ridiculous. It's just so OTT. I can picture Jen-Hsun Huang twirling his mustache and laughing maniacally like some kind of comic book villain. Next we'll be hearing about him catching kittens, puppies and babies on bayonets. It makes me wonder if a overvolted (voltmodded?), overclocked, watercooled GTX480 could beat a current-limited, essentially clock-locked GTX580. I'd like to see that comparison.