UFS 4.0 is the next flash storage specification, but what does it mean for you?

If you’ve heard about UFS 4.0 but aren’t sure what to expect, then you’ve come to the right place.

UFS 4.0

Your next flagship smartphone will likely have UFS 4.0, or Universal Flash Storage 4.0. A bigger version number usually means better, but what exactly does that mean for you? Why is UFS 4.0 an improvement over UFS 3.1? What even is UFS?

Universal Flash Storage: Its advantages over eMMC

Universal Flash Storage (UFS) is a standard designed and incremented by Joint Electron Device Engineering Council (JEDEC), a global organization that designs open standards for different electronic systems. JEDEC published the UFS 4.0 standard in August 2022, with the last update being UFS 3.1, which was published in 2020.


UFS has one clear advantage over eMMC, and that’s its full-duplex interface. Half-duplex can be visualized as a one-way street; traffic can flow one way or the other, but not both simultaneously. This means with eMMC, you can only read or write, but not both. In contrast, UFS can do both at the same time, which allows for read and write operations in parallel.

These are the maximum rated speeds achieved by eMMC vs UFS 3.1 and UFS 4.0. Keep in mind that there are very few smartphones being released with eMMC storage nowadays and that any flagship released in the last year or two is pretty much guaranteed to be using either UFS 3.0 or UFS 3.1.

Sequential read (MB/s) Sequential write (MB/s) Random read (IO/s) Random write (IO/s)
eMMC 5.1 250 125 11000 13000
UFS 3.1 2100 1200 100000 70000
UFS 4.0 4200 2800 N/A N/A

If you look at the above table, UFS 4.0 has some pretty big improvements. The reason storage speed is so important is that moving large files from your phone’s storage to your phone’s memory is limited by the speed of the storage. You can have the fastest chipset in the world, but if you have slow storage, games will still take a long time to load and your phone will still take a long time to switch on.

Where does UFS 4.0 improve on UFS 3.1?

Let’s address the numbers that people care most about first: UFS 4.0 is a lot faster than UFS 3.1. It doubles the sequential read from 2.1GB/s to 4.2GB/s and more than doubles the sequential write to 2.8GB/s from 1.2GB/s. Those are massive improvements and will improve the speed at which your phone launches apps and saves files to your storage.

However, speed isn’t all there is. Samsung, the company that had the pleasure of unveiling UFS 4.0, says that it also consumes 46% less power than UFS 3.1. It says that you’ll consume approximately 1mA per 6.0Mbps transfer speed, though the current isn’t a great measure of power consumption. It is likely that this was measured when the phone’s battery was at its nominal voltage (or 3.6v/3.7v). Storage is far from the biggest battery consumer in a smartphone (that definitely goes to the chipset and the display), but any and all power efficiency improvements are welcome.

On top of all of that, UFS 4.0 modules are tiny. Samsung says they’re only 1mm thick, with a maximum size of 13mm long and 11mm wide for a 1TB module. That’s a lot of storage in a small package and ensures that there’s more room for other components inside the limited space of your devices.

When will phones get UFS 4.0? Should I upgrade?

If you’re looking to get your hands on a phone with UFS 4.0, you’ll be glad to know that most modern flagships have this upgraded storage available. The Vivo X90 series got it first, and other companies weren’t far behind. The OnePlus 11, Samsung Galaxy S23 series (aside from the base model S23), and countless other flagships have it, too.

As for whether you should upgrade solely based on UFS 4.0, the answer is almost certainly no. While there are substantial improvements here, they won’t be that noticeable because there will likely be diminishing returns from such large improvements. If a game’s loading speed is decreased from five seconds to four seconds, is that really worth paying several hundred dollars for an upgrade?

As a result, UFS 4.0 is one of those improvements you’ll benefit from when you upgrade, but you definitely shouldn’t upgrade because of it. Improvements are always being made for smartphones, and faster storage won’t make everything magically better. Chipset improvements are still going to be the most noticeable upgrades, even if those improvements are diminishing now with each and every generation, too.