[benplumley]

How about "50% faster" and "50% as fast"? If these are different (which to my ear they clearly are), then "200% faster" and "200% as fast" are different too. Naturally it's all quite ambiguous so whoever's writing the press release can pick the more impressive meaning in each case.

[mkl]

To me percentages behave differently from "times". I agree with you on the percentages but disagree on "times faster" and "times as fast", which I think are the same.

[IanCal]

The key difference in my reading here is the use of percentages or x, where x I read as "times". I would never expect someone to say "half times faster".