Microsoft used Windows 8 as a guise under which to revamp the engine, and the results is a much faster system that consumes fewer resources than before. This makes it a better choice than Windows 7 for low-end PCs.
The redesign opts for simple colours and fewer visual effects, also contributing to the increased speed due to resources saved compared to the Aero Glass effect of Windows 7.
Overall, Windows 8.1 is better for everyday use and benchmarks than Windows 7, and extensive testing has revealed improvements such as PCMark Vantage and Sunspider. The difference, however, are minimal.