"The use of OpenDocument documents is slower to the point of not really being satisfactory," Alan Yates, the general manager of Microsoft's information worker strategy, told ZDNet UK on Wednesday. "The Open XML format is designed for performance. XML is fundamentally slower than binary formats, so we have made sure that customers won't notice a big difference in performance."
Yates cited a study carried out by ZDNet.com that compared OpenOffice.org 2.0 with the XML formats in Microsoft Office 2003. But Marino Marcich, the managing director of the ODF Alliance, said this was not a fair comparison, as it did not test Open XML itself and examined only one implementation of the OpenDocument Format (ODF).
"There's simply no Open XML product on the market yet, to compare performance," Marcich said. "ODF is supported and implemented not just by OpenOffice, but by multiple applications including StarOffice, IBM Workplace, KOffice, Abiword/Gnumeric and Google Writely. All these applications have different performance behaviors."
He added that OpenOffice.org was not initially optimized for ODF, but will be in the future.
Marcich said Open XML is harder for companies to implement as it has more than 4,000 pages of documentation, compared with 700 for ODF.
"A skeptic might say the documentation is so long so only one application will support it well," he said. "On my initial reading of the (Open XML) documentation, it looks like Microsoft is trying to reinvent the wheel, while ODF freely refers to existing standards like SVG," or Scalable Vector Graphics.
But Yates said the Open XML documentation is longer because it is covering more functionality.
"The documentation is so much deeper than that for the OpenDocument Format--it represents much more functionality, many more options and a deeper, richer customer experience," Yates said.
Earlier this month, the International Organization for Standardization, a move research firm Gartner predicted would of getting Open XML approved by ISO.
Yates disagreed with Gartner's analysis and said there was "plenty of room for multiple document formats."
The Gartner analysis "was very surprising and ill-informed," he said. "We've encouraged the analysts to gather more data and understand the depth of the situation."
Last week, ECMA International, a European standards body, published an intermediate draft of the Open XML format. ECMA is expected to make a decision about the format by the end of the year, according to Yates.
Ingrid Marson of ZDNet UK reported from London.