Introduction of 4K Alignment – Get Best Performance of 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.

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.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.

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.

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.

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.

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.