Running from a fast internal SSD, the portable version is 90-95% as fast as the installed version. Running from a USB 3.0 drive introduces noticeable lag but remains usable for lighter edits. Avoid USB 2.0 entirely.
: While specific to the portable build, standard Photoshop 2022 requirements generally recommend a minimum of 8GB of RAM (16GB or more preferred) and a compatible GPU. adobe photoshop portable 2022 v23.3.2.458