Windows Vista is here. The long-awaited operating system is set to grace current and future builds of desktop and laptop manufacturers as of the end of January. PC Magazine managed to get our hands on some of the first systems releasing with the Vista OS, and what we found may surprise you.

For starters, Vista isn't necessarily that much of a performance upgrade from XP than one might expect on desktops. On laptops, however, systems under Vista were sometimes slower than under XP. Confused? Don't worry, we break down the performance for you.

Resource Library:

Click here to read about how Microsoft is making it easier to get Vista online.

It's important to note from the get-go that the Vista-equipped systems (both desktops and laptops) were not tested against one another. Rather, we were comparing the performance of the systems under Vista versus their performance under the XP OS. Thus, any Editors' Choices that were awarded were for their category.

For the desktops we tested, we asked each manufacturer to include hard drives with both XP and Vista on them so that we could swap out the drives to test under both operating systems. With certain exceptions, which we'll get to, the desktops received less of a performance "hit" from switching to Vista than laptops.

Two of the desktops we tested—the all-in-one HP TouchSmart IQ770 PC (which is the Editors' Choice for all-in-one desktops) and Dell Dimension E521—came with 2GB of system memory. The gaming-oriented Gateway FX530XT (Vista) came with 4GB of RAM, which can finally be addressed by Windows Vista (XP Home and Pro had trouble recognizing all 4GB, even though it "supported" a max of 4GB). (Note: We couldn't test the HP IQ770 with Windows XP because the system was designed from the ground up to work with Vista, and as such, XP drivers weren't available.)

Read the full story on PCMag.com: Putting Windows Vista PCs to the Test