While the final hardware requirements for Microsoft's Windows Vista operating system won't be made public until next summer, testers say the first beta release of the operating system is performing moderately well on existing PC hardware.

Microsoft released to testers the first beta of Vista one week ago. As it has been doing for the past couple of years, Microsoft is declining to specify the minimum hardware requirements for the operating system for now

Microsoft did offer some general guidelines, saying that Vista beta 1 should run on "a majority of modern computers that can run Windows XP, carry the 'Designed for Windows XP' logo, have a mainstream processor from Intel or AMD, and have 512 MB of RAM," a Microsoft spokeswoman reiterated this week.

(Comparatively, Microsoft suggests that users have a 300-MHz CPU and 128 MB of RAM to run Windows XP.)

So do Microsoft's guidelines meet the mark?

"Beta 1 seems to be working well enough, although I'm extremely disappointed in both Microsoft and NVIDIA for not delivering drivers that would enable me to experience (Vista's Aero) Glass (user interface) in its full glory," said Chris Pirillo, founder of Lockergnome.com and a frequent Microsoft beta tester. "Either 64MB ain't enough video RAM, or NVIDIA is incapable of supporting this card with this beta (and possibly future releases). Frustrating."

Pirillo said he is testing Beta 1 on a Toshiba Satellite 5105-S701 that originally shipped with XP Home Edition. The system sports an Intel Pentium 4 processor, 512 MB of RAM, a 60GB hard drive. It also has a 15-inch display and an Nvidia GeForce4 440 Go graphics card with 64MB of video memory.

So far, Vista "doesn't seem to be any faster than XP," Pirillo said. "Maybe a little slower."

The bits released on July 27 have yet to be performance-tweaked. Microsoft officials warned the first beta would include little of the final user interface.

But Pirillo said that the "'Classic Mode' interface is beyond unusable," and called it a "Frankenstein UI."

"I'm going to reserve true judgments until one of the first RCs (final release candidate builds), he said. But "if certain details are still underfinished, I'll scream like a banshee."

Another beta tester, Robert McLaws, president of Interscape Technologies Inc., is having a different and better experience with Beta 1, which he is running on a new Toshiba Tecra M4, with a Pentium 4 processor, 1 GB of RAM, a 60 GB hard drive and an Nvidia GeForce Go 6800 TE graphics card with 128 MB of video memory.

"Performance-wise, Vista is running very well. It feels a lot more stable than Windows XP," McLaws said. "It starts up quickly, applications load faster, and even the networking stuff performs better. The only real problem I've experienced is that, when I shut down, I can never actually get the machine turned off. It hangs at the shutdown screen."

But nVidia driver problems also are cropping up for McLaws, as "nVidia/Toshiba don't have LDDM drivers for the graphics card in my Tablet."

" nVidia drivers have brought up a BSOD (Blue Screen of Death) or two... probably because nVidia's drivers are terrible so far," McLaws added.

However, McLaws said, "I was really impressed with the Supplemental Driver Pack idea. It even had drivers for most of my Toshiba hardware. The only additions drivers I had to snag were the Tablet-related ones (button drivers, etc.)."

Another Vista tester, who requested anonymity, also commented on the poor support for nVidia cards so far.

The tester noted that "Beta 1 doesn't have 2D acceleration when you're running Aero Glass.This can affect performance significantly. But that is something that is certainly going to be addressed in upcoming betas."

The tester said that he has installed Beta 1 on various Pentium 4-based machines with 500 GB of hard drive. He has run both ATI and nVidia graphics cards.

"ATI support is better than nVidia in Longhorn beta 1 so far," he said.

But, "overall, for a first beta, it's pretty solid," the tester concluded.