The tests involved every possible permutation of new and older AutoCAD formats, two different WAN bandwidths (1Mbit/s and 10Mbit/s), an ISP of 0 (full scrambling) or 50 (partial scrambling), and what the test report calls major and minor file changes. With four binary factors and four pairs of devices, that meant Riverbed's technicians ran 64 different tests in total.

The Riverbed results, which have been validated by storage analyst firm Taneja Group and are available online (more registration needed - sorry!), show that all four vendors suffered similarly from the change in file format. With ISP set to 0 they were still able to accelerate the file-save process, presumably by optimising the network and application protocols, but not to reduce the amount of data transferred.

However, by far the biggest gain in save-speed for AutoCAD 2007 came not from different de-duplication technology, but from changing the ISP setting, as Autodesk had already advised users to do.

"We don't dispute they do de-duplication differently, but we're confident it's irrelevant - at the end of the day, we're all substituting a small amount of data for a large one," asserted Alan Saldich, Riverbed's VP of of product marketing and alliances.

He added: "Silver Peak is just trying to get PR - we've proven they're wrong, and caught them with their pants down. We'll publish details of our tests, and we welcome people replicating them."

Looking forward, it seems quite likely that the skirmishes will continue as the vendors all seek to give themselves a leg up in this combative market.

Hopefully though, at least one good thing will have come out of it all. That's the growing realisation that just as networks and storage can no longer operate in isolation, but must take account of their effects on application performance, so must application designers take account of their effects on the rest of the infrastructure.