SAS or SATA: which is better and what are the differences?

Interfaces like SATA and SAS allow motherboards to interface with HDDs and SSDs, allowing them to load operating systems, run programs, and do almost everything computers can do. However, with so many different uses it’s easy to get lost in terms like SAS or SATA. What are? How do they differ? Which one should you choose?

SAS or SATA: which is better and what are the differences?

What is SATA?

The SATA or Serial Advanced Technology Attachment connector uses the standard 15 power pins and seven data pins. SATA drives are more popular because they prioritize storage capacity over speed, resulting in cheap and easily available mass storage.

However, the fact that SATA drives focus on storage capacity does not mean that they are slow. Most consumer SATA drives start at 5400 RPM, but can go up to 7200 RPM. Although SATA drives are not as fast as SAS drives, they are more than enough for most people to use their computers.

SATA drives are also cheap, so they’re the perfect storage solution for most situations, like running a DIY NAS or regularly backing up data. Even as SSDs gain ground, SATA HDDs continue to be popular for mass storage.

What is SAS?

SAS stands for Serial Attached Small Computer System Interface. It uses a connector similar to SATA, also using 15 pins for power and seven for data transfer. However, the split on the SATA connector between the power and data transfer pins is not as prominent.

SAS drives are faster and more reliable than SATA drives in terms of data transfer. A SATA connector is fast at storing data, but output data is not transferred at the same speed. SAS solves this problem by transferring outgoing data as quickly as incoming data.

They are typically used in enterprise-grade applications and servers designed to run 24/7. According to Toshiba, one of the world’s most popular HDD manufacturers, the mean time between failure (MBTF) for SAS drives is 1.4 to 2.5 million hours of use between 5 and 55 degrees Celsius. In contrast, the MTBF of general-purpose SATA drives is only about 600,000 hours of use at the same temperature.

However, they consume more power and it is common practice to have a SAS drive loading the OS on a server and use SATA drives for storage. This is also done because SAS drives focus more on data transfer speeds than storage, which means SAS drives over 500 GB can be quite expensive.