Turn off Superfetch and prefetch to increase Vista boot speed

Vista boot slow shutdown Start slow how to solve | Turn off Superfetch and prefetch. Many friends on the Internet are talking about the slow start of vista. Most of them have two aspects:

1. The problem of hardware configuration, especially the memory is less than 128MB, and the memory is less than 512MB.

2, hardware conflicts and driver mismatch (of course, due to these reasons, the startup is slow, exist on all windows systems)

In fact, there may be another reason: superfetch, This was originally a new technology for Windows Vista to speed up system operation.

But in fact, on some slow-drive devices, such as laptops, turning it off can improve system responsiveness. I tested it on my laptop, turned off superfetch, and observed that the power is turned on until the user logs in. That is to say, after the login, the hard disk light is no longer on, and the time required for this process is saved about 5-7 minutes.

When understanding why superfetch affects system startup speed, we need to explain a few techniques to fully understand their principles.

Virtual memory, including Windows, has been using virtual memory. Its role is that when physical memory does not meet the needs of the application, the operating system will start to put the application in memory. The data is stored on the hard disk, freeing up RAM for other uses. The data that is stored to the hard disk is stored as a file, usually in the root partition, a hidden file called Pagefile.sys.

When you need to call this data, the operating system looks up the data in the pagefile and returns it to memory. In this process, the application may be slow to respond due to the need for repeated disk reads and writes.

Prefetching Prefetch So when it comes to Windows xp, the operating system designer has designed a technique for pre-reading Prefetch, which monitors data on disk and memory during system or application startup. The rules or conditions of movement between the two, in advance, the data with high read and write frequency is saved to the file with the .pf extension in the %systemroot%\\Prefetch folder, and these files are stored in a regular and efficient manner. In this way, when the data is repeatedly read, it can be read directly from these cache files without re-reading the hard disk sectors and tracks, and finding the original location of the data, which naturally accelerates the response speed of the application. . But the main caching method for this technology is still disk-based.

Fast read-ahead Superfetch to Windows Vista, because the computer's memory has grown, designers have begun to consider using memory as a pre-read cache data storage space. However, for two reasons, a memory is incomprehensible. Once the power is turned off, all data will be lost. Second, the memory is not large enough to accommodate all applications. Therefore, the read and write operations of Superfetch are mainly based on memory. However, while data is being written to the memory, it is still written to the hard disk for data exchange. This data exists as a file, usually where they are stored in the %SystemRoot%\\Prefetch directory with a .db extension.

At the same time, because Superfetch technology is built on Prefetch, Vista has also enabled Prefetch while enabling Superfetch, which further exacerbates disk read and write. If your computer's hard drive speed happens to be slow, such as a notebook's 5400 rpm hard drive, then Superfetch will slow down your system.

Solving the problem We understand the working principle of Superfetch, and it is not a problem to solve the slow system startup. The following adjustments to Superfetch can be done through the registry. The registry key for superfetch is

HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Control\\Session Manager\\Memory Management\\PrefetchParameters

So you can increase Vista startup speed and application response speed, you can consider three Ways:

1. Adjust the superfetch cache level.

The key name is EnableSuperfetch

The key value is 0=Deactivate 1=Superfetch Application 2=Superfetch Launcher 3=Superfetch Both

The default value is 3, you Try adjusting these values ​​and feel the response speed of the system or application after the adjustment.

2, close prefetch or superfetch

Prefetch key name is EnablePrefetcher, the key value is set as above. You can set either or both to 0 to turn them off to reduce disk reads and writes.

3, using readyboost

At this point superfetch will transfer the cached data files to the flash storage. The flash storage prepared for Readyboost is faster than the 5400-rpm notebook hard drive. I have tried one, the general flash copy data, about 3-4MB /s, and the readyboost flash can reach 10MB /s. So using the technology of readyboost, on the one hand, accelerates the performance of superfetch, on the other hand, it also reduces the reading of the hard disk, so that your computer can respond faster when it is running.

Others As for the effect of turning off superfetch on hibernation, I have not tested it. Everyone is interested to test it.