Windows Vista: Beta 2 Preview

Performance Improvements

The last significant group of core improvements to be found in Vista is a collection of several changes Microsoft has made to various subsystems in order to boost overall system performance. Unfortunately, because Vista is still in a beta state where performance optimizations have yet to be turned on, not to mention the lack of diagnostic programs to test these features, we won't be able to bring you any meaningful performance numbers until the release version of Vista ships. However, we can talk some about the most important of these features.

Since XP was launched 5 years ago, broadband internet access has come to be the dominant connection method in much of the world. While XP had some targeted improvements to increase performance on these connections, Microsoft is taking it one step further in Vista with a heavily modified TCP/IP stack. The primary changes will be that the stack is now capable of a greater level of self-optimization by automatically adjusting some settings to maximize performance, and some overhead has been removed to better reach the maximum theoretical performance of high-speed LANs (GigE and higher). The new stack also has support for both IPv4 and IPv6 (instead of requiring 2 separate stacks as is currently the case), but the amount of hardware support to go with this is still fairly low.

The I/O subsystem has also been given a major overhaul, and like the forthcoming changes with DirectX 10, the focus is on better ways to schedule and execute I/O tasks. I/O tasks can now be given a priority level, so that unimportant tasks such as virus-scanners can be given a lower disk priority that will prevent them from being so detrimental to system performance.

The I/O system will now also be able to handle Microsoft's SuperFetch technology, which promises to improve memory usage by creating a third tier of memory pages between those important enough to be in RAM and those relegated to being in a pagefile. The new tier will be a class of pages that are important enough that they need to be accessed often, but are small pages that don't take much time to transfer; these pages can be stored in connected flash-memory devices which offer latencies measured in nanoseconds (a couple orders of magnitude faster than a hard drive page file), and in turn free up the main memory for more important tasks. It's an interesting idea that we hope will give some real benefit in the release version of Vista, and is likely to become more important in the near future as hard drives start to be released with integrated flash memory buffers.

Lastly, the kernel itself has been slightly overhauled, implementing new methods of memory and task management. Microsoft's pitch here is that it will be better optimized for dual-core systems, but since the NT kernel has always had a good level of SMP support for multiple processors, we're a bit skeptical on just what kind of performance improvements can be found here.