It's likely "real". By real, I mean that I just ran JSBench on my MacBook Air with Safari and Chrome (latest released version of each) and Safari came out significantly ahead (Chrome took 1.75x longer). They're claiming 2.53x faster than Chrome in that slide so that would mean an improvement of probably around 50% over the current Safari in terms of JS speed on this benchmark. So, it would seem that this particular benchmark already favors Safari's JS engine and that the next Safari will improve on the current Safari's performance.

Now, the issue with JSBench is that it's real-world JS, but only from 5 sources. Granted, they're 5 sources that are very high-trafficked, but it's still a small sample size (http://jsbench.cs.purdue.edu/).

Similarly, Apple showed off SunSpider benchmarks showing the next Safari being faster than Chrome. The current Safari on my MacBook Air beats Chrome, with Chrome taking 6.9% longer. So, part of it is that each browser maker has its preferred benchmarks.

Why would it BS? This is almost always the case. Safari has plenty of notches on it's belt, it's just that the Chrome and FF teams do far tighter release cycles allowing for improvements like this to be pushed out the door faster.

Safari is a great browser, always has been. This is hardly surprising or new, just like it's not novel that Chrome will meet and exceed those stats within a month or two of the release of Safari 7.

Its's real. You can try the benchmark yourself here, and learn how it is different from other JS benchmarks <http://jsbench.cs.purdue.edu/>.

Seems BS to me. Looks just like their "performance" pages for the Macbook Pro on the Apple website.

I'm going with BS until they provide more details. They don't even mention what version of Chrome and Firefox they are testing against.