Windows 8 Support for Low-Power Graphics Hardware

Packed with support for a far wider range of graphics than previous platform releases, Windows 8 will deliver great visual experiences even when loaded on low-power hardware, Microsoft promises.

The company explains that Windows 8 was designed from the ground up with support for a diversity of hardware configurations, and the trend is accelerating. The Redmond-based software giant focused both on making the new OS compatible with new, high-performance graphics cards, as well as with the increasing range of low-power mobile devices. By making this move, Microsoft made sure that the platform would be loaded on the wider array of hardware than ever before, and that users would enjoy a great experience even on low-power devices. In fact, the company notes that Windows 8 devices will span “from graphics hardware that consumes on the order of 1 watt in always-connected tablets all the way up to high-end systems with multiple graphics cards that use a total of 1,000 watts or more.”

“This broadening diversity brings with it new design considerations,” Rob Copeland, the group program manager on Microsoft’s Graphics team, explains in a blog post. However, the main idea was to deliver a “visually compelling, high-performance experience” to users, even if they enjoy Windows 8 on highly mobile devices, in which the battery is the primary power source. Battery life needed improvements, but the performance levels of the device were not to be forgotten either. Thus, new GPU architectures emerged from Microsoft’s hardware partners, to ensure that all goes according to plan. When designing Windows 8 for use on low-power graphics hardware, Microsoft focused on optimizing the graphics architectures called “tile-based rendering,” commonly used in such devices.

The idea behind this architecture is that the graphics engine uses a high-performance (but small) memory cache. The GPU renders the screen in tiles (sections), processing the same set of commands for each tile, and not for the entire screen. “The intent is to minimize operations that use memory off-chip, therefore keeping power consumption low and performance high. Repeatedly accessing memory off-chip is expensive both in terms of time and power consumption,” Copeland explains. For increased efficiency, Windows 8 comes with additional flags, hints, and new APIs, all of which were meant to minimize the number of times the tiles are rendered. “We have incorporated the use of these into the Metro style app development platform to ensure greater efficiency in apps running on graphics hardware that uses a tile-based rendering architecture,” he continues.

Microsoft also looked into another means to reduce power consumption. One of them involves performing graphics rendering calculations using fewer bits of precision. “For Windows 8, we added new mechanisms for apps to specify the amount of precision needed in their graphical calculations,” Copeland notes. “For example, when doing custom blending of multiple images where the image data is 8 bits per component, the blending computations could be done with 10 bits of precision rather than the default of 32 bits. The reduced precision doesn’t impact image quality, but does reduce power consumption.” The upcoming operating system will arrive on shelves with support for the widest array of graphics hardware ever, spanning from high-end gaming rigs to light-weight, always-connected tablets, he concludes.

Windows 8
Images credits to Microsoft

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