Others may have been reluctant to start their Vista upgrades because of the dearth of information until now on SP1, which some say is a new, deliberate strategy under new Windows chief, Steven Sinofsky.
"If you're a large IT buyer, you crave info," Kleynhans said. "At the same time, nothing good comes from telling the entire world what you're going to do. So it will be interesting to see if Microsoft can strike the right balance."
What to expect from Vista SP1 and XP SP3
All told, SP1 will include 19 major changes. One will make the much criticized User Account Control (UAC) security feature less intrusive and annoying to users, Zipkin said.
"We are working to remove a few prompts, but at heart, it's still the same UAC, because to do its job, it still has to pop up and quiz you," he said.
Copying and unzipping files in Vista should also be much faster, Zipkin said, as should the ability of Vista PCs to wake up from standby or hibernate modes.
For laptops, Microsoft has fixed problems in the way Vista communicates with certain video cards and chips. Fixes should improve battery life, Zipkin said, as well as make them work better with external displays.
The Bitlocker drive encryption, which formerly could only encrypt the C: drive, can now be used to encrypt other partitions and hard drives.
One key change that users might not notice, Zipkin said, is the addition of application programming interfaces (APIs) in 64-bit versions of Vista that allow security software to access the Vista core kernel. Vendors such as Symantec and McAfee had complained bitterly last fall that Microsoft's kernel patch protection feature, which was designed to make Vista more secure, also effectively disabled their security software.
Among other changes are improving the performance of domain-joined PCs when the PCs operate off the domain; improving overall performance of Internet Explorer 7 by reducing CPU utilization; and fixing a problem in which there is a 10-second delay between the time when Ctrl-Alt-Del is pressed and the password prompt is displayed. SP1 also supports new hardware and hardware standards. For example, the service pack adds support for the exFAT file system, which will be used by flash memory storage and non-computer consumer devices. It will also add support for Direct3D 10.1 and add APIs for 3D applications, aimed at games developers.
It is also aimed at Vista deployment, management and support, including changing the way that Group Policy is managed. SP1 will uninstall the Group Policy Management Console (GPMC) and by default, GPEdit.msc will be used to edit local Group Policy. Administrators will have the option of downloading a separate module that will let them add comments to Group Policy Objects (GPOs) and search for specific settings.
Finally, SP1 lets users disable Vista's built-in search engine and use an alternate, such as Google Desktop. This was a change mandated by the U.S. Department of Justice after Google Inc. complained.
There are no changes to Vista's virtualization features, Zipkin said.
As for XP SP3, the main new feature is Network Access Protection (NAP), now available only in Vista. NAP reports the security status of PC to a Windows Server, which can quarantine the PC and block any network traffic to and from the computer if it appears compromised.
Hugging the middle of the road?
For consumers and small businesses, SP1 will come in the form of a 50MB .exe file. For corporations using Windows Server Update Services, System Center Configuration Manager 2007, or other professional deployment tools, SP1 will come in the form of either 32-bit or 64-bit 1GB files; some of the bulk can be chalked up to the inclusion in those files of every single language version. The deployment tools will help push out only the needed updates and right language version to each PC, Kleynhans said.
Windows Genuine Advantage (WG) validation will not be performed when SP1 is downloaded and installed.
Brett Waldman, an analyst at IDC, said the changes between Vista and SP1 are minor enough that most applications tested for Vista should work fine under SP1. "It's really more of an incremental update," he said.
Kleynhans agreed. "As far as service packs go, this is middle-of-the-road -- not too risky, and relatively uneventful," he said.
On the other hand, "there are still a lot of things that really need to be in Vista for the OS to really take hold," said Kleynhans, referring to well-publicized device and software compatibility problems with Vista.
Zipkin asserted, however, that Microsoft has made tremendous progress. As of last month, more than 2.2 million devices now support Vista, up from 1.5 million last November. 2,076 applications are now certified as working with Vista, up from 254 in November.
They include a number of virtual private networking (VPN) and enterprise anti-virus software, Zipkin said, that previously failed to work well with Vista.
Preston Grall contributed to this report.