The M5 SSD's performance uplift was fairly substantial, even when compared to the prior generation.

> In the Blackmagic Disk Speed Test, the SSD in the M5 MacBook Pro achieved read speeds of up to 6,323 MB/s, compared to just 2,031 MB/s on the M4 MacBook Pro. It's not like the M4 is "slow" in a vacuum, but the M5 SSD is over three times faster, which is a great generation uplift.

https://www.tomshardware.com/laptops/macbooks/m5-macbook-pro...