Optimization techniques for solid-state drives under Windows 7

When Microsoft developed Windows Vista, solid-state drives were not so hot, so they were not optimized. Windows 7 is different, Microsoft from the beginning of the solid state hard disk in a key position, and recently through the official blog detailing the new system of the corresponding optimization measures.

First, solid state hard disk performance degradation and trim request operation

Flash blocks, pages, and cells must be erased before they can write new data, so the newly purchased SSD is performing well, but it can feel a performance drop after a long time, before Intel tries to fix it by upgrading the firmware.

Microsoft says they have also observed this phenomenon, but not as badly as everyone thought, in fact, in addition to the benchmarking, the user in the day-to-day operation of the basic feeling is not different.

Of course, manufacturers still have a duty to maximize the maintenance of high performance. Hardware manufacturers first in the solid state hard drive before the factory in advance of its total erasure (similar to the hard drive low-level format), the second is to prepare a dedicated space to store a dense burst of writing, enterprise-class hard disk will even retain up to 50% of the space, in order to maintain a high long-term continuous write speed

Microsoft has also used a "Trim" mechanism in conjunction with solid-state hard disk manufacturers. In Windows 7, if the SSD report supports the trim attribute in the ATA Protocol DataSet Management (DSM) command, the NTFS file system will require the ATA driver to issue a new trim operation instruction to the solid-state drive when the user deletes the file, telling it that the relevant pages can be safely erased. After the solid-state drive gets this instruction, it will not be in a hurry to perform the erasure operation, but to wait until the appropriate opportunity, that is, the time to write again, because the relevant pages can be reused, there is no need to perform erasure operations.

For example, if a 128KB chunk is stored in a 128KB file, if the file is deleted and the trim operation is performed, the SSD can avoid mixing the bytes in the block with the other bytes required for subsequent writes to the block, which can greatly reduce the "wear" of the solid-state drive.

In Windows 7, the trim request is not limited to a delete operation, but also to full integration of partition and volume level commands, file system commands, and System Restore capabilities.

Second, Windows 7 optimization and default behavior brief

On a solid-state hard drive, Windows 7 disables disk defragmentation because the random read operation mechanism for solid-state drives is good, and defragmenting files is no longer helpful.

Windows 7 also disables SuperFetch, ReadyBoost, and startup and program prefetching by default on solid-state hard disks, which are designed for traditional hard disks.

The built-in partition creation tool for Windows 7 also takes into account the characteristics of solid-state drives. Of course, it's best to put the system partition on a solid-state drive.

Third, FAQ

1. Will Windows 7 support trim?

Support. See above.

2. Do you disable defragmentation by default on solid state drives?

Yes. Defragmentation of Windows 7 excludes SSD partitions, and defragmentation ignores it if the hard disk partition has more random read performance than 8mb/s.

8MB/S This indicator is the internal analysis of Microsoft, will be included in the final version of the system. In fact, this regulation is not significant, because solid-state drives are generally in 11-130mb/s, and the test of the 182 traditional hard disk only 6 more than 2mb/s, all others in 0.8-1.6mb/s.

3. Will the SuperFetch be disabled on solid-state drives?

Will, but not absolutely.

Microsoft originally intended to completely disable SuperFetch on the SSD, but encountered a significant performance decline on some systems, and later found that the random writes and erasure operations of the first generation of solid-state drives were too frequent, resulting in extremely slow read speeds, and the opening of SuperFetch and other prefetching techniques Performance is obviously picking up.

4. Does NTFS compress folders and files on solid-state drives?

Compressing files helps to free up free space, however, compression, decompression requires additional CPU resources, in the notebook will also be more power consumption, so it is only suitable for infrequently used files to do this operation, and frequently read and write files and folders do not need to, such as My documents, such as temporary Internet folder.

5. Does Windows Search index differ in solid-state drives?

No.

6. Is BitLocker optimized for solid-state drives?

Yes, on the NTFS file system. BitLocker is read, encrypted, and written for the entire partition, and the NTFS file system helps the solid-state drive optimize this operation through the trim command.

7, Media Center configuration on the solid state drive will be different?

No. Media recording and playback are mostly continuous operations, and now the unit capacity of solid-state drives is much more expensive than traditional hard drives, so saving and backing up is still the preferred mechanical hard drive.

8. Does the write cache make sense for solid-state drives? If the solid-state drive supports write caching, what does Windows 7 do?

Some solid-state drives in addition to flash chips, the main controller, but also add a certain amount of RAM as a cache, which is modeled on the traditional hard disk to cache write. For this type of device, the erase and write commands in Windows 7 are expected to remain at the same level as traditional hard drives.

9. Does raid make sense for solid-state drives?

Yes. Solid-state HDD raid can achieve higher performance and reliability than mechanical hard disk raid.

10. Should the paging file be placed on a solid-state drive?

Yes. Most paging file (Pagefile.sys) operations are small random reads or large persistent writes, which are the best places for solid-state drives.

After thousands of tracking of paging file read and write, Microsoft found that the paging file read and write ratio is 40:1,67% read less than 4KB, 88% less than 16kb,62% write is not less than 128KB, 45% is exactly 1MB.

In short, there is nothing more suitable for a solid state drive than a paging file.

11. Is it good to put a dormant file on a solid-state drive?

No. Hiberfile.sys are read and written in chunks, so they are all the same on mechanical or solid-state drives.

12. How does the Windows Experience Index adjust to the performance of solid-state drives?

Windows 7 has added some new random reads, Random writes, and erasure evaluations. A good solid state hard drive score will be above 6.5, the highest score of 7.9, the measurement period of 1.9 points, 2.9 points and other abnormal evaluation will not appear again.

Of course, if the SSD itself is normal, the score in Windows 7 will be similar to Windows Vista and will not go up.