ReadyBoost: Better Windows Vista Performance In A Flash

Vista's optimized caching features turn flash drives, flash cards, and new hybrid hard drives into booster rockets for OS performance.
ReadyBoost-Ready Motherboards
Another way to utilize ReadyBoost is to buy a motherboard with flash memory installed. The first of these are already on the market, introduced by ASUS a week before Vista's official birthday on January 29, 2007.

New motherboards from ASUS include flash memory on the board that can be allocated as a ReadyBoost cache.

There are four models in the series: a Plus and a Premium model each for the Intel Core 2 Quad and the AMD Athlon 64 FX processors. All include several Vista-specific features, but most important in the current context is their ASAP ("ASUS Accelerated Propeller") feature which is, essentially, a 512MB flash drive soldered to the board. The flash is recognized by Vista as an external drive, and can be used for whatever you'd use a flash drive for, including, of course, ReadyBoost.

ReadyDrive: Bringing The Boost To Hard Drives
ReadyDrive does for hard drives and flash memory more or less what ReadyBoost does for system memory and flash drives. This new feature of Vista takes advantage of equally new hybrid hard drive technology that combines conventional rotating storage with flash memory.

All hard disks have some RAM built into them as a cache, but it's there just to buffer reads and writes, and it's volatile -- its contents evaporate when the drive powers down. Adding nonvolatile flash to the drive does something entirely different from buffering I/O. It means that, in effect, the drive can be on even when it's off. This can save not only time but battery power, if the PC running Vista happens to be a laptop (and increasingly, they are -- laptop sales have equaled or bettered desktops in recent years).

That's why the first hybrid hard drives just beginning to reach the market are 2.5-inch laptop drives. Samsung announced early in March that it had begun shipping samples of its first H-HHD, and Seagate is expected to follow suit any day.

Samsung's FlashON hybrid hard drives combine rotating storage with 256MB of flash memory to enhance the speed of laptops running Vista. (Click image to enlarge.)

The Samsung drives in the 2.5-inch FlashON series will combine 80, 120, or 160 gigabytes of rotating storage with 256MB of flash memory. Seagate's first drives will be in the same configuration -- 2.5-inch drives with 256MB of flash, and the company has said it will produce drives with larger flash buffers of 512MB and 1GB in the second half of 2007.

That 256MB of flash will be shared among several separate cache functions, according to Ruston Panabaker of Microsoft's Windows Hardware Innovation Group, who gave a presentation on ReadyDrive at last year's Windows Hardware Engineering Conference (WinHEC 2006):

  • About 10MB of it will be devoted to caching the hard drive's firmware.

  • The next 32MB will be used as a write cache. Laptop drives spin down to save power, and a write cache in flash means that writes can be accumulated and the disk left off longer.

  • Another 32MB will be available for caching data and program code that supports hardware features and Vista's new Windows HotStart function. (HotStart ties a program function to a hardware button so that users can do things like run a media player, or browse and play files from the hard disk, or open an e-mail program with one click, whether the laptop is on, sleeping, in hibernation, or off.)

  • Whatever flash memory is left is set up as a ReadyBoost that SuperFetch will use to cache code pages while it works to maintain optimal memory content, and to accelerate the boot and resume processes.

This not only improves the laptop's performance, according to Panabaker, but it can save 4 to 12 percent of the machine's battery by allowing the hard drive to power down while the flash cache stays on to serve cached code to the CPU and aggregate writes to the disk.

ReadyBoot: A Flash Booster Rocket For Boot-Ups
ReadyBoot may be a little too much like ReadyBoost to be clearly differentiated, but maybe that's the point. After every boot-up, the ReadyBoost service does an analysis of the files read during the last five boots, then builds a list of the files it predicts will be used in the next boot in what order, and their locations on disk. When the PC boots up, the ReadyBoost service creates a compressed cache of those files. That serves the right files in the optimal order to boot the machine faster.

If the computer is equipped with an H-HHD, ReadyDrive can accelerate the boot process even more. When a shut-down or hibernation is initiated, ReadyDrive loads data required early in the boot process to the H-HHD's flash cache. When the disk is powered on again, even though it won’t spin up for 2 to 4 seconds, data can start flowing from the flash memory almost immediately.

Ready? Boost!
ReadyBoost isn't a magic bullet for Vista performance. There is no substitute for system memory, so if you're going to run Vista, load up on as much as your machine will hold or you can afford, depending on which limit you hit first. But if you've got a machine with a limited amount of system RAM -- an older PC or a laptop -- flash memory and the ReadyBoost technology that's in every copy of Vista can make a difference. An "Enhanced for ReadyBoost" flash drive or card can give you an immediate shot in the arm -- and, when they get here, hybrid hard drives could help as well.

Those technologies aren't the end of the line, by any means. As Panabaker pointed out, with ReadyBoost there's a direct relationship between flash memory performance and Vista performance gains -- and the performance of flash memory interfaces has been doubling every year. As Vista is adopted by more and more PC users, the result will undoubtedly mean more flash in our future.

Editor's Choice
Brandon Taylor, Digital Editorial Program Manager
Jessica Davis, Senior Editor
Cynthia Harvey, Freelance Journalist, InformationWeek
Terry White, Associate Chief Analyst, Omdia
John Abel, Technical Director, Google Cloud
Richard Pallardy, Freelance Writer
Cynthia Harvey, Freelance Journalist, InformationWeek
Pam Baker, Contributing Writer