The evolution of SSD memories, with great capacity and speed, has led to a change that not everyone is aware of. Saving free space can help improve its performance.
Filling your SSD to the max might not be the best idea. It’s true, the ever-increasing storage capacity can tempt you to squeeze it to the limit, and yet, especially if it’s your primary drive, this can lead to a loss in performance.
When you delve into the universe of SSDs, you soon discover technical terms such as “SLC cache”, which, although not mentioned in all advertising brochures, play a fundamental role in the performance of the drive and is a fact to keep in mind. account when purchasing.
In simple terms, modern SSDs divide their storage into fast and slow parts. Think of it like a highway: you have fast lanes for fast vehicles and slower lanes for trucks and heavier vehicles.
In an ideal world, you would always want to be in the fast lanes. The fast part of an SSD is its cache. The more you fill your SSD, the fewer fast lanes you will have available, making your data transfers considerably slower.
To give an example, in a recent experiment, published by Xda-developers, with the Western Digital WD Black SN770M SSD, it was observed that With only 10% of its space filled, it reached speeds of 4,800MB/s. But when it was 90% full, those speeds plummeted to 1,200MB/salmost four times slower.
Where does the SLC cache come from?
According to the experiment itself, It all goes back to the evolution of SSDs. Initially, they were made with SLC chips that stored a single bit of data. There was no cache and they were fast and reliable. But as demand for storage grew, manufacturers began developing cells with more bits.
Chips emerged that stored 2, 3 or even 4 bits per cell (MLC, TLC and QLC). However, handling more bits complicated things and slowed down the speed. The solution was to create this space that, although part of these new cells, would act like the original SLC speedster. This is the “pseudo SLC” or our fast lane on the highway.
Although it may seem unintuitive, to maintain optimal performance on your SSD, it is advisable not to fill it completely. The general rule of thumb might be to keep your primary SSD drive no more than 70% full and secondary SSDs up to 90% full.