In the third of our four-part series on Windows Vista, we look PC performance issues

Although many cosmetic and usability improvements have been made in Vista, this is far from the whole story. By taking advantage of modern hardware and employing new optimisation techniques, Vista delivers a significantly more responsive experience than Windows XP.

Its self-tuning and self-repair abilities also help to improve performance over time and reduce the typical degradation we’re used to seeing in Windows as applications are installed and uninstalled over a period of months or years.

Perhaps the biggest bottleneck in PC performance is disk I/O and some of the biggest performance advances in Vista are concerned with minimising the need for hard drive access. Vista’s memory requirements are higher than those of Windows XP, but not mainly because of poor memory management.

In fact, it’s quite the opposite – Vista is better equipped to take advantage of large amounts of physical memory and employs techniques to make the best use of modern Flash memory.

Superfetch
Memory management is key to good system performance: the operating system needs to decide which data needs to be kept in Ram and which is best swapped out to disk. This usually results in the most recently accessed data sitting in Ram until the memory is needed for something else.

Vista’s new Superfetch technology takes a more intelligent approach to memory management by taking into account what tasks you’re doing and what state the system is in.

When you’re hard at work at the keyboard, priority needs to be given to foreground applications, but when the PC is idle it’s best to give background processes priority. These could be tasks such as virus and spyware scans or disk defragmentation.

When you return to work, the system memory will be left as it was when the background tasks finished, causing your applications to run more slowly as the system memory is repopulated with application data.

Superfetch gets around this by returning the application data to memory as soon as the background tasks complete, while the PC is still idle. If it gets it right, when you return to work the system memory should be returned to the state it was in before the background tasks were started.

Superfetch also keeps track of which apps you use and pre-loads them into memory to increase start-up speeds. Vista ships with Superfetch pre-seeded with data by Microsoft to boost performance right from the first boot.

This information is then updated over the lifetime of the PC to match usage patterns more closely. It’s intelligent enough to keep track of which programs you use on which days of the week and to manage system memory on that basis, learning over time.

The goal of Superfetch is to load into memory the data you need before you actually need it, cutting out waiting time and eliminating sluggish behaviour. This may result in a system that becomes faster the more you use it, reversing the tendency of PC performance to deteriorate over time.

With multicore processors forging ahead, the gulf between CPU power and hard drive performance grows ever wider. Superfetch narrows that gap by helping to ensure the processor cores aren’t kept waiting for data.