However, it is widely perceived that the release significantly benefited Windows users once it could be swallowed, particularly in the area of improving security.
Some Microsoft partners have also alluded to the update publicly.
On 19 April, Intel CEO Paul Otellini was asked how Vista sales would impact his company's 2007 sales projections on a conference call, and he replied that "[Vista] deployment [in enterprises] will actually happen when the Service Pack gets released in the fourth quarter time frame, probably the October-November time frame."
Sources close to Microsoft have confirmed that the company is currently testing SP1.
The blog poster, former Microsoft employee Ethan Allen, owner of the The Hotfix blog and Web site is predicting that SP1 will include device driver and software compatibility technology that many users had hoped would be available in the OS from the start.
Among them could be support for third-party USB and Firewire devices such as digital cameras, in particular products from Sony Corp. that have been having compatibility problems with Vista, Allen said.
There also will be patches to improve the TV playback and other Media Center capabilities in Vista, as well as to repair inconsistencies with the power management functions such as sleep and hibernation modes, he said.
Allen claims that Vista SP1 will not include a heavy dose of security updates.