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20 June 2019  Amanda J. Brook  Senior Product Manager
 

Summary
Purchased SSD and want to get best performance of the SSD? Maybe you need to get more about 4K alignment and how to achieve 4K alignment for your SSD!



Purchasing a new SSD for your computer and make the replacement. However, you are sad to find that the actual performance is much lower than the manufacture claims to be after testing the SSD with software. This problem could be caused by the 4K alignment.

What is 4K Alignment?

With the development of the times, hard disk capacity is continuously to be expanded. And one sector of traditional HDD is fixed for 512 bytes. And in SSD which is using NAND flash  memory, 512 bytes per sector is changed to 4K bytes per sector. This is now called “4K sector”.
“4K alignment” is to align physical disk partition with computer logical partition and ensure reading/writing efficiency of hard disk. When we are creating partitions on hard disks which use 4K physical sector, the partition always does not start from the starting position of a physical sector. Similarly, writing a file will operate 2 physical sectors at least, which definitely will increase writing times and waste disk space.
what is 4K alignment
In other words, when we save a 4KB file in SSD which is not 4K alignment, the file will be saved in 2 different sector. So does reading. After 4K aligned, the files can be saved and read in one 4K sector, which can greatly improve the reading/saving time.
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Is 4K Alignment Necessary?

We can make comparison of the reading and accessing time for 4K alignment: After 4K alignment, the reading and writing speed got greatly improvement. As we all know. the performance of SSD depends on the reading/writing speed. As we can see, 4K alignment does help SSD to maximize its performance and speed up your PC.
If SSD is not 4K aligned, the data will be save in 2 cluster. Even we save the smallest file, it will still be saved in 2 4K clusters. In this way, when we want to get/save data from the disk, the file system will read and write two physical cluster, which will reduce reading and writing speed and shorten the service life of SSD. So, it is necessary to make 4K alignment for SSD.
Before 4K aligned
AS SSD Benchmark will show “BAD” on the left-top corner if SSD is not 4K aligned.
before 4k alignment
After 4K aligned
AS SSD Benchmark will show “OK” on the left-top corner if it is 4K aligned,
after 4k alignment
*Definition of the test:

1. Seq = Sequential speed          2. 4k = Random 4k speed

3. 4k64 = Random 4k speed (64 queue depth)   4. Acc.time - Data accessing time

From the running test above，the reading value almost the same. But the Sequential writing speed improve almost 60%! Besides, the improvement of the two 4K writing speeds is great as well: 5 times! The improvement is so obvious.

How to Check whether SSD has 4K Aligned?

4K alignment is very common for us and we can check the SSD with some third party software like AS SSD Bencnmark. Besides, we can also check the 4K alignment with build-in tool in Windows easily. Here we go.
1.  Press “Win” and “R” button in Windows or click the “Start” button, in the “Run” edit box, type “msinfo32″, and then press the “Enter” key.
keyboard
2. Find “Components” in “System Information”. Then please click “Storage” then “Disk”. Check the “Partition Starting Offset” value. If the value can be divided by 4096, then the SSD is 4K aligned.
partition strarting offset

How to Achieve 4K Alignment for SSD?

If you partition with the system built-in tool in Windows 7 or later versions, the partition, after being formatted, will be 4K aligned (2048 sectors) by default. So, users don’t need to make any further settings. If the system you are using is the one before Windows 7, you need to achieve 4K alignment with some third party software like Disk Genius.

Here, if you want to migrate Windows system to SSD without reinstalling, Renee Becca is the best choice for you. It will achieve 4K alignment automatically at the same time when migrating system.

More about Renee Becca >>How to Migrate >>

Here, if you want to migrate Windows system to SSD without reinstalling, Renee Becca is the best choice for you. It will achieve 4K alignment automatically at the same time when migrating system.

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