High-density displays in computers are becoming more common. The wave that began with the Retina MacBook Pro and continued with the Chromebook Pixel is now washing over the Windows world. Toshiba's Kirabook was the first, but there were plenty of others announced at Computex. We're sure they'll begin to trickle down into cheaper devices as the year continues.

To prepare for these new laptops and displays (and to catch up to where high-PPI display support is in both OS X and Chrome OS), Microsoft's freshly-announced Windows 8.1 is making a few small but important changes to how the operating system handles them. We installed Windows 8.1 to the Kirabook to investigate.

Different displays, different densities

Windows 8.1 definitely seems to be doing some automatic display scaling here, as has been rumored based on beta builds of the OS. In both Windows 8.1 and the preview of Windows Server 2012 R2, as long as a proper graphics driver was installed, Windows would automatically scale the Kirabook's screen to around 150 percent.

Dive into the manual settings and you'll find a few things that weren't here before. If the "Let me choose one scaling level for all my displays" box is checked, you'll see the same old percentage-based scaling options as before. Whatever percentage you choose will be universally applied through the entire operating system on all of your displays.

On the Kirabook, a 200 percent scaling option has now been added to the 100, 125, and 150 percent options from post-Vista versions of the operating system. You could set the scaling level to 200 percent (or any number, really) through a custom setting (as we found when we installed Windows 7 on the Retina MacBook Pro), but 8.1 exposes the scaling setting to make it easier to access.

Things get more interesting when you choose to scale different displays independently. Make sure the "Let me choose one scaling level for all my displays" box is unchecked, and the list of percentages will change into a more user-friendly slider that makes UI elements larger and smaller. Using the same under-the-hood calculations by which it scales the UI automatically, Windows will tell you what the "recommended size" is for the display that you're on. We left the setting at the recommended size for good measure.

We then connected a second monitor to the Kirabook, a 21.5-inch 1080p screen from Samsung. Rather than scale elements on that display to 150 percent, Windows would automatically rescale application windows as we dragged them back and forth between the screens. You could actually use Windows 8.1 as-is to drive an external display or projector from a notebook with a high-PPI screen. You wouldn't have to deal with overly large images on the external displays or overly small images on the built-in one.

This isn't to say the implementation is perfect. When you drag a window from the Kirabook's high-PPI screen to the external one, the window doesn't change from something rendered at 150 percent scaling to something rendered at 100 percent. Rather, Windows takes the 150 percent-scaled window and resizes it on-the-fly to be the same size as the same window rendered at 100 percent. The results are the same as they might be if you took a large image and shrank it down: fine detail is sacrificed, and windows on the external display were subtly blurry (enlarge the screenshots below to see the difference).

This effect was even more obvious if I set the external monitor to be my primary display and then dragged windows onto the Kirabook's screen: windows rendered natively at 100 percent scaling were blown up to be the size of 150 percent scaled windows. Text and images were as pixelated as they would be if you blew up a small image. In each case, Windows seemed to use the primary display's scaling settings as the "canonical" ones and would resize windows up and down from there.

Microsoft's solution for multiple monitors is workable, and it's definitely better than it was in Windows 8 or any prior version. Previously, the scaling settings felt more like an accessibility option than a real, fully implemented feature, something to be used to prevent eyestrain on a standard monitor rather than drive displays with over 200 pixels-per-inch. At least now the settings are being tweaked with high-PPI laptops in mind.

That said, Windows 8.1 does not somehow fix the inconsistent behavior of third-party desktop apps when you're using Windows' scaling features. The Start screen and apps from the Windows Store mostly look great, but on the desktop the state of things is the same as it was when we reviewed the Kirabook. Some applications just look blurry, some are crisp but exhibit odd rendering problems, and others ignore the scaling settings entirely.

The fault here doesn't lie with Microsoft but with the third-party developers. We'll just have to hope that the coming wave of high-resolution hardware (as well as Microsoft's own attention to the issue) will convince developers that implementing proper scaling support is worth their money and time.

What has changed for the better is the way that the operating system has been tweaked to accommodate high-resolution, high-density displays. We'd like to see more granular settings for controlling the scaling on each display by the time the final version of Windows 8.1 is released later this year, but for a preview this is a not-inconsequential step forward for people interested in high-PPI laptops.