The sad reality is that everyone does this. This is the primary reason it annoys me when people use SunSpider as a cross-platform benchmark: SunSpider these days is a test of how well your JS engine cheats at SunSpider, nothing more. nVidia started "optimizing" for 3DMark in their drivers almost a decade ago when their FX series struggled to compete legitimately, and today both companies do this sort of thing regularly and extensively - how do you think nVidia or AMD can release a driver that magically doubles performance in some new title? Heck, what do you think that 'free' marketing money that companies get for tacking a "Plays best on Intel" or "The Way It's Meant To Be Played" logo at the start of their game is really paying for?
This is, regrettably, the way of the industry now. And when journalists report results like SunSpider and GeekBench and GLBenchmark and make sweeping judgments of device performance based on them, they're only encouraging this sort of hackery.
