which bore the headline "Weighing the cost of Linux vs. Windows? Let's review the facts" offered a comparison between a Windows and a Linux machine, which, according to the software giant, demonstrated that "Linux was found to be over 10 times more expensive than Windows Server...for Windows-comparable functions of file serving and Web serving.
"The results showed that IBM z900 mainframe running Linux is much less capable and vastly more expensive than Windows Server 2003 as a platform for server consolidation," according to the ad.
The Advertising Standards Authority (ASA), however, thought the choice of hardware could have been more appropriate, saying: "The measurements for Linux were performed on an IBM zSeries, which was more expensive and did not perform as well as other IBM Series."
Microsoft said the machines were as comparable as possible--a Linux image on IBM's z900 mainframe CPUs and a Windows Server 2003 image running on two 900MHz Xeon CPUs--and wasn't hardware specific.
The ASA, nevertheless, thought consumers might not see it that way and that the "Windows vs. Linux" stance might lead people into thinking running Microsoft's OS--not the "competing file serving set-ups"--was cheaper than one based on Linux.
The group has asked Microsoft to amend its ads and urged the company to in the future be advised on its campaigns by the Committee of Advertising Practices' Copy Advice Team.
Jo Best of Silicon.com reported from London.