By Emily / Last Updated April 15, 2022


“I just got a new Western Digital hard drive and it says if I want to use more than 1 large partition I must align the partitions at first. What should I do to align the partition on my Western Digital hard drive? Any suggestion will be appreciated in advance!”

Wd My Passport Ultra


Before figuring out what is (Western Digital) partition alignement and how to realize it, we need to understand some basic concepts about hard drive. Modern hard drives have two sector sizes: physical sector size and logical sector size. The physical sector size is what the disk actually reads and writs in while the logical sector size is what you can ask it to read and write in. And to use a hard drive for data storage, we need to initialize, partition and format it first of all.

To put it simply, we have to create at least one partition on the disk. The partition works like a container with a file system and it contains several coniguous sectors. Formatting is to specify how to use the inside sectors. This process will divide all sectors in the partition into several groups by a fixed cluster value from begining to the end, and they will be numbered in sequence. Every cluster may contain one or more logical sectors. After formatting, the partition will read and write data by this smallest unit: cluster.

Benefits of performing Western Digital Alignment

Dividing a hard disk into partitions is based on the logical sector unit, and each partition can start and end on any logical sector. If the partition start position is not aligned to the edge of a physical sector, then all clusters in the partition won’t be aligned to the edge of any physical sectors after format. Look at the following picture, every physical sectors is composed of 4 logical sectors, and the partition starts from the logical sector 3. In this case, every cluster occupies 4 logical sectors; but the cluster does not align to the physical sector edge, so each cluster span 2 physical sectors.

Not Aligned Partition

Therefore, when the disk reads the inside data, it will have to access more than one physical sector. For example, if it reads data inside the 4 logical sectors in the cluster 0, the disk will access data in the physical sector 0 and 1, and logical sector from 0 to 7. Likewise, the writing process will also take the same procedures. As a result, the disk read and write performance will decreased significantly. That’s why many users find their disks, espeically SSD runs slow.

Aligned Partition

So, if the partition starts from the edge of any physical sector (refer to the above picture), the partition starting position is aligned to the physical sector 1 edge, every cluster takes up 4 sectors and they all align to the edge of the physical sectors. Under this situation, the disk does not need to read extra physical sector and the disk performance will be improved. That’s the biggest benefit of partition alignment.

Best Western Digital alignment software

To align Western Digital hard drive, especially the SSD drive, the most convenient way is to employ a proper partition alignement software, such as AOMEI Partition Assistant Professional. It can help finish all SSD or HDD partition alignment easily and effectively in Windows 10, 8, 7. You can download its demo version for a free trial.

Try Demo Win 10/8.1/8/7/XP
Secure Download

Notice: If there are other applications running on the partition you are going to perform, close them or go into PreOS Mode to operate it.

Step 1. Install and run AOMEI Partition Assistant Professional. Right click the specified partition and select “Advanced” > “Partition Alignment”.

Ssd Alignment

Step 2.In the pop-up Window, set the sector of partition to align. Here we align partition in 8 sector. Actually, you can use the default size too.

8 Sector

If the partition is already aligned correctly, AOMEI Partition Assistant will give you information to notice as “Then current partition has aligned to the selected sectors, and it does not need to align it again”.

Step 3. After that, it will go back to the main interface. Preview the result and click “Apply” > “Proceed” to complete this operation.

Apply Alignment

Before you perform partition alignment task, you can also check if there is any errors on that partition. You can follow these steps to check partition via AOMEI Partition Assistant: “Partition Menu” > “Advanced” > “Check Partition”.

Check Partition


It’s rather simple to align Western Digital hard drive partition in Windows 10/8/7 as long as you employ an appropriate alignment tool. After that, your Western Digital SSD can perform better than before.

Besides partition alignment, AOMEI Partition Assistant also provides you with many other advanced functions, such as clone hard drive (HDD, SSD, USB flash drive, SD card, etc), clone partition, transfer OS to SSD, allocat free space from one partition to another, quick Partition, secure erase SSD, wipe hard drive and so on. If you are a Windows Server users, you can try the AOMEI Partition Assistant Server edition.