Ubuntu – How to partition a Advanced Disk HDD properly using Gparted or similar

The older hard drives used smaller 512-byte sectors; recently newer drives use larger sectors, usually 4096 bytes.

Software, however, is still sees the disk in 512-byte "logical" sectors, although it often reads the data in 4K chunks

When creating a partition, it is important to align the beginning of the partition with the beginning of the large physical sector, otherwise each read will require reading 2 physical sectors, which will affect performance.

As you can see, your partition starts from logical sector #3 (#1 and #2 take 512*2=1024 bytes), so to fix the problem you need to move the start of the partition by 3072 (4096-1024) bytes.

Newer versions of gparted are aware of this - just boot from Ubuntu LiveCD and create a new partition selecting the default alignment option (which is "align to 1 MB", which is optimal even for larger sector size, such as in SSDs).

If you already installed OS and do not want to re-create partitions, you could move the start of the partitions to align properly, but that would involve some pen-and-paper calculations. Also, you'll need to reinstall the bootloader if you moved Ubuntu partition.