Imagine walking into the CIO's office tomorrow and saying, "I can cut our WAN consumption by as much as 80 times, speed file transfers as much as 45 times and make our Windows users a whole lot happier." Think you'd get the CIO's attention?

Those aren't just idle claims. Seven months of rigorous testing showed us why application acceleration is such a hot area: These devices really work.

We tested boxes from Blue Coat Systems, Cisco, Riverbed Technology and Silver Peak Systems in a true enterprise context, with a massive test bed pushing data over multiple T-3 and T-1 links (see "How we did it"). After pounding the systems with the most popular enterprise applications, we're inclined to believe the hype.

Even if average speedups are "only" around 5 to 10 times, that's still a big improvement. With 31% of IT budgets eaten up by recurring monthly WAN costs, according to a recent Nemertes Research study, application acceleration promises potentially huge cost savings.

Riverbed's Steelhead appliances outperformed the field in most tests, and won our Clear Choice award.

But all these devices deserve serious consideration: Blue Coat's SG appliances for solid HTTP optimization; Cisco's Wide Area Application System (WAAS) for excellent compression, traffic transparency and interoperability with other devices; and Silver Peak's NX appliances for strong scalability and intuitive traffic reporting tools.