Boost Vista Performance with ReadyBoost

Just when system builders finally have XP down to a science, along comes Microsoft's new Vista OS—and with it, a new batch of headaches. For one, Vista brings a completely new and unfamiliar look-and-feel to the Windows desktop. For another, the bare OS consumes nearly 11 GB of disk space all by itself.

On the plus side, one of the Vista's most useful new features is a utility called ReadyBoost. This utility lets a user to plug in a compatible Flash drive and turn over some (or even all) of the drive's storage space to the OS. Vista can then use the Flash drive as part of its own cache, in addition to however much RAM is already installed on the computer system.

This is important because the OS or system cache is invariably the biggest consumer of RAM on any Windows system. (If you don't believe this, just look in the Physical Memory pane in Task Manager at any given moment.) As a result, by deploying ReadyBoost, you can measurably boost the performance of Vista systems.

Unfortunately, ReadyBoost does come with a few "gotchas." First and foremost, not just any Flash drive will be suitable for such use. According to Microsoft, to qualify for its "Enhanced for ReadyBoost" product designation, a Flash drive must deliver a certain level of read/write performance. More specifically, says Matt Ayers, a program manager in the Microsoft Windows Client Performance Group, a qualifying Flash drive must support throughput of at least 2.5 MB per second for 4,000 random reads, and at least 1.75 MB/sec. throughput for 512,000 random writes. In other words, many Flash drives--especially older ones—are too slow for ReadyBoost.

Going deeper into Vista's ReadyBoost, I discovered a few other limitations:

• Only USB Flash drives currently work for ReadyBoost use. This means that flash card readers, multimedia or memory cards such as SD, MemoryStick, MMC, and so forth--which also typically work through card readers of one kind or another—won't support ReadyBoost. That's true even if the media is fast enough to meet ReadyBoost read/write speed requirements.

• ReadyBoost cache space tops out at 4 GB, so there's no point in trying to increase ReadyBoost storage beyond that limit. When I tried to do so as an experiment, Vista seemed to delight in resetting the ReadyBoost cache size to some size smaller than 4 GB, with no discernable pattern in its settings.

• ReadyBoost cache may be allocated on only one suitable device at a time. Even though you may have several open USB ports on a PC and numerous ReadyBoost-capable Flash drives, you can use only one at a time.

• When you eject a ReadyBoost-capable Flash drive from a Vista machine, the reserved space for the ReadyBoost cache on the drive is also removed. This means that the next time you plug the drive back into a Vista machine to use it as a cache extension, you'll have to set ReadyBoost up all over again. But if you just yank the drive, it appears as a file named ReadyBoost.sfcache on that device, and the space remains inviolate, even on other Windows OSes. Therefore, to keep using a Flash drive for ReadyBoost, don't use the Explorer Eject function or the Remove Hardware Safely widget that Vista so thoughtfully makes available on the taskbar. Instead, simply remove the Flash drive from its USB port. That way, you'll be able to resume ReadyBoost the next time you plug that drive back in.

Nonetheless, ReadyBoost is pretty cool, as it does markedly improve Vista's performance. I will describe more included improvements later on in this Recipe by comparing benchmarks. But first, let's give ReadyBoost a whirl and see how it can work for you.