Microsoft-sponsored study says Vista improves TCP/IP performance

Companies that deploy Windows Server 2008 and Windows Vista in tandem could see more than a threefold increase in networking performance for file transfers, downloading roaming profiles for mobile users and accessing files on a portal, according to a Microsoft-commissioned study conducted by the Tolly Group.

In a 38-page white paper set for publication Wednesday and titled "Enhanced Network Performance with Microsoft Windows Vista and Windows Server 2008," the Tolly Group compares the networking performance for file access on WANs and LANs using various configurations of Windows Server 2003 R2 or 2008 on the backend and XP SP2 or Vista on the frontend.

Not surprisingly, the combination of the newest operating systems brings the best gains in network performance in large part, Tolly concludes, because of an upgraded TCP/IP stack and updates to the file-sharing Server Message Block (SMB) protocol.

The report was commissioned by Microsoft, which raises questions about the value of the results, but the conclusions should at least provide some benchmarks for corporate users testing the software as part of their adoption evaluations.

Microsoft has been touting the networking benefits of its new operating systems on the client and server, and this study finally attaches numbers to those claims.

“We think the gains that we showed are considerable,” says Kyle Sim, director of engineering for Tolly. “Because just by changing the OS on the client or server [or both], you can see performance enhancements of two to three times.”

The Tolly study found that just by upgrading to Vista, users can see throughput gain of two to three times over XP and a reduction in time-to-completion (the time it takes to download a 10MB Office file over a simulated 10Mbps WAN) of 60%. The study shows that Vista in combination with Windows Server 2008 can yield gains of as much as 3.3 times in throughput and 3.5 times in time-to-completion over Windows Server 2003 and XP.

Tolly ran the tests over a variety of simulated LAN and WAN configurations taking into account bandwidth and latency The tests included sending SMB Copy and Open file commands, copying Roaming Profiles (including all elements on a user’s desktop) and executing an Open file command on a SharePoint Services portal across the WAN and performing Office Open and Copy files commands across the LAN.

On the WAN side the connections ranged from satellite-type connections at 512KB per second with 300 milliseconds of latency to 10MB per second with 50-millisecond latency. On the LAN, the connections were 1000MB per second with 1-millisecond delay and 100MB per second with a 5-millisecond delay.

In one sample test, Windows Server 2003 R2 server was able to copy to an XP client a 10MB Office file at an average throughput of .9MB per second in 93.07 seconds using a simulated 2MB per second WAN link with 150 milliseconds of latency. In contrast, the Windows Server 2008/Vista combination had a throughput rate of 2MB per second and a completion time of 42.85 seconds, doubling throughput and cutting the download time by more than half.