Windows Vista Security: Praxisorientierte Sicherheit für Profis

Optimizing Performance

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Using ReadyBoost to Enhance Performance

Windows Vista uses your computer’s disk drives for paging files and system cache.

Because reading from and writing to a disk is significantly slower than reading from

and writing to physical memory (RAM), this can cause performance bottlenecks that

make your computer seem sluggish or unresponsive. To reduce the performance

impact related to reading and writing the system cache, Windows Vista introduces

Windows ReadyBoost.

Windows ReadyBoost is a feature that lets you extend the disk-caching capabilities

of the computer’s main memory to a USB flash device. Using flash devices for cach-

ing allows the operating system to make random reads faster by caching data on the

USB flash device instead of your computer’s disk drives. Windows Vista can read

flash devices up to 1,000 percent faster than physical disk drives, significantly boost-

ing the overall performance of your computer.

The types of USB flash devices you can use with Windows ReadyBoost include:

• USB 2.0 flash drives

• Secure Digital (SD) cards

• CompactFlash cards

Figure 3-23. Viewing your computer’s DEP configuration

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Chapter 3: Fine-Tuning Windows Vista’s Appearance and Performance

Further, these devices must be at least 512 MB or larger and have sufficiently fast

flash memory. Because some flash devices have both slow and fast memory, you may

find that Windows ReadyBoost can use only a portion of the memory on the device.

Windows Vista can use an amount of flash memory equal to twice the amount of

physical memory (RAM) on the computer. Therefore, if your computer has 1 GB of

RAM, you could use up to 2 GB of memory on a flash device to boost your com-

puter’s performance.

When Windows ReadyBoost is enabled, Windows Vista uses the USB flash device

primarily for caching that uses random input/output and small, sequential input/out-

put rather than large, sequential input/output. This is because the memory on USB

flash devices is better suited to random I/O and small, sequential input/output than

large, sequential I/O.

Because USB flash devices are meant to be portable, Windows Vista adds protections

to prevent the sudden removal of a USB flash device from crashing the computer and

to prevent reading of any sensitive data written to the flash device. To allow a USB

flash device to be removed at any time, Windows Vista ensures that all data writes are

made to the hard disk first and then copied to the flash device. This eliminates the

potential for data loss when removing a flash device. To prevent reading of sensitive

data, Windows Vista encrypts all data written to a flash device so that it can be used

only with the computer on which it was originally written.

Enabling Windows ReadyBoost

You can enable Windows ReadyBoost by completing the following steps:

1. Insert a USB flash device into a USB 2.0 or higher port.

2. The AutoPlay dialog box should be displayed automatically. If you always want

to use the device with Windows ReadyBoost when inserted, select the “Always

do this...” checkbox.

Windows Vista should display the AutoPlay dialog box automatically.

If it doesn’t, you’ve probably selected the “Always do this...” check-

box previously. You can clear a previous selection by clicking Start

➝

Default Programs. On the Default Programs page in the Control Panel,

click “Change AutoPlay settings.” On the AutoPlay page, scroll down

to the bottom of the page. Click “Reset all defaults” and then click

Save. Remove the USB flash device and then reinsert it to display the

AutoPlay dialog box.

3. If the flash memory performs at a sufficiently high speed, Windows Vista will

display a “Speed up my computer” option in the AutoPlay dialog box. Select the

“Speed up my system using Windows ReadyBoost” option.

4. Windows Vista extends the computer’s physical memory to the device. The

default configuration enables Windows ReadyBoost to reserve all available space

on the device for boosting system speed.

Optimizing Performance

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If you previously inserted a flash device and declined to use Windows ReadyBoost,

you can enable ReadyBoost by completing the following steps:

1. Click Start and then click Computer.

2. Right-click the USB flash device in the Devices with Removable Storage list and

then choose Properties.

3. Click the ReadyBoost tab, as shown in Figure 3-24.

Figure 3-24. Configuring Windows ReadyBoost