https://wccftech.com/m1-macbook-air-ssd-speeds-2x-as-fast-previous-model/

The 2020 MacBook Air, a model which has now been discontinued by Apple in favor of the M1 MacBook Air, was criticized for having slower SSD speeds. The company has made changes to this in the latest version, which features the custom 5nm M1 chip and, alongside it, a faster SSD, according to these tests.

One MacRumors forums member going by the username abbotsford1980 tested out the M1 MacBook Air SSD and got some impressive results if you compare them to the 2019 and 2020 MacBook Air model sporting an Intel CPU. The surprising thing about the previous-generation Intel versions was the one launched back in 2018 actually had a faster SSD than its successors. However, it also arrived at a higher starting price than the newer versions.