Perhaps you saw the mainstream press breathlessly reporting Apple’s announcement that its upcoming Power Mac G5 system would be the “world’s fastest personal computer,” based on independent benchmark testing.

It’s not the first time Apple has used phony benchmarks to make outlandish claims, and this one unraveled practically before Steve Jobs left the stage after making the announcement. Here’s the summary of Apple’s latest debacle from Paul Thurrott’s newsletter:

”During his keynote address at the Worldwide Developers Conference (WWDC) 2003 in San Francisco earlier this week, Apple Computer CEO Steve Jobs told the excited audience that the company’s new Power Mac G5 systems–due in August–wouldn’t just match but would surpass the performance of similarly equipped high-end Pentium 4 and Xeon-based PCs from companies such as Dell. ‘We are delivering today the world’s fastest personal computer,’ Jobs said during the address, although the Power Mac G5 systems won’t ship for 2 months. Apple has made similar performance claims over the years but has always relied on rather spurious evidence, such as handpicked benchmarks that highlight specific strengths of the PowerPC platform. However, this time, Jobs touted several so-called industry-standard benchmarks from VeriTest, which reputedly backed up Apple’s claims. Has the Macintosh really surpassed the PC, after years of lagging behind?

“Sadly, Apple’s claims are as questionable as ever, but the astonishing part of this story is how quickly the truth came out. Almost immediately after the keynote address, while Macintosh fanatics worldwide continued chortling over their perceived victory, people around the Web began looking into the benchmarks Apple used to prove the Power Mac G5’s prowess. Predictably, things aren’t as simple as Apple’s followers would like to believe. More alarming, even dual-processor Power Mac G5 machines still don’t match the processing power of a single-processor Pentium 4 system, contrary to what Apple announced Monday.

“Here’s why: In a bit of classic benchmark trickery, Apple’s systems were highly tuned in nonstandard ways to provide the best scores on specific benchmarks. Meanwhile, the PCs used to compete against the Power Mac G5 were saddled with generic tools. Furthermore, advanced Pentium 4 features such as hyperthreading were turned off, artificially lowering that system’s scores. VeriTest also has results for various Pentium 4 systems in which these features were enabled. Guess which system, Mac or PC, came out ahead then? . . .

“Sure enough, in each of the benchmarks in which Apple claims victory over Pentium 4- or Xeon-based systems, various Pentium 4, Xeon, and even AMD Athlon Windows XP systems routinely beat the Power Mac G5 when the tested systems were properly configured and didn’t have features turned off.”