When Windows Vista premiered, one of its less-understood new features was ReadyBoost, which accelerates certain disk operations by caching the results on a flash drive. People misinterpreted it as a way to use flash memory as RAM -- a mistaken belief that lingers to this day, even as Windows 7 has made ReadyBoost all the more powerful. What ReadyBoost actually is and what it does (and doesn't do) for enterprise PCs deserves a full explanation.
What ReadyBoost is (and isn't)
Windows Vista and 7 use a caching technology called SuperFetch to speed up the loading of commonly accessed files on disk. The SuperFetch cache is built over time. As you run programs and access certain files repeatedly, they are added to the cache, decreasing the time required to read those files and launch those programs.
ReadyBoost takes this cache and moves it from a contiguous portion of the hard drive onto a flash drive. It's tuned for optimizing nonsequential reads, which slow down hard drives the most and benefit most from being read from local memory or something faster than a hard drive. It is not a substitute for RAM -- no more so than a swap file on disk is -- and it does not add the kind of performance you'd get by adding more RAM to a system.
So, is there any benefit at all to using ReadyBoost in an enterprise setting? The short answer is "Yes," but it's a highly qualified yes.
Where it makes sense
Enterprises depend on fleets of machines, such as notebooks, desktops and servers, that have different price tags and life spans. Systems whose practical use can be extended a few years by spending $100 on a memory upgrade are not likely to be replaced wholesale. So if it's possible to get that much more performance out of a desktop by spending $10 on a flash drive, who wouldn't do that?
ReadyBoost's performance gains are most dramatic on systems that only have about 512 MB to 1 GB of RAM. This isn't to say that systems with more memory don't manifest an improvement, just that the improvements are most notable on lower-end machines. Both Tom's Hardware and AnandTech ran their own analyses and drew similar conclusions.
ReadyBoost can also assist computers with slow hard drives of 5,400 RPM or less. The total gain is incremental rather than dramatic, but ReadyBoost does improve certain behaviors, such as the subsequent openings of applications and application shutdown.
For systems with slow hard drives or low RAM, ReadyBoost is a pretty good interim measure until you can replace them or upgrade their RAM. However, if you have a choice between spending $10 on a flash drive or $40 for a RAM upgrade on a given system, and there's no real pressure to spend less, then the RAM upgrade will be far more worthy an investment.
Proper use of ReadyBoost
If you do plan to use ReadyBoost in enterprise machines, keep the following in mind:
USB access is required. If your enterprise has a lockdown policy for USB devices, you may not be able to enable ReadyBoost unless you can grant exceptions for specific machines. Granting USB access to any machine that does not already have it will create a security hole, so if your organization has concerns about trust or sensitive information, ReadyBoost may not be easily implementable.
Format ReadyBoost drives as NTFS, not FAT32. ReadyBoost stores all of its data on a given drive in a single contiguous file. If you have a flash drive larger than 2 GB, it'll need to be formatted as NTFS. FAT- and FAT32-formatted drives can't store single files larger than 2 GB, so everything over the 2 GB boundary is unused and, therefore, wasted. Also, as of Windows 7, you can now use ReadyBoost on volumes larger than 4 GB, so the more space you have to throw at the problem, the better. (The maximum size for any ReadyBoost cache is 32 GB.)
Not all flash drives are created equal. Flash drives vary enormously in terms of read and write speeds. When you set up a flash drive for ReadyBoost, Windows tests it to determine its speeds and may reject it if it doesn't read and write quickly enough. Some flash drives are marketed with the slogan "Enhanced for Windows ReadyBoost," but that doesn't mean those are the only drives that work with ReadyBoost. In addition, you may be better off looking up a particular make and model of drive. You might have drives lying around that are perfectly adequate.
Give the system time to populate the ReadyBoost cache. ReadyBoost's effects don't show up instantly but instead happen over time as the user runs applications, opens documents and gives the cache things to do. It may take the better part of a day's use before ReadyBoost's full effects become apparent.
ABOUT THE AUTHOR
Serdar Yegulalp has been writing about personal computing and IT for more than 15 years for a variety of publications, including (among others) Windows Magazine, InformationWeek and the TechTarget family of sites