According to TheGamePost the cards are the slowest of all options
"A new speed test using
Mario Kart World on the Switch 2 compared loading times across three storage options: built-in
internal storage, SD Express memory cards from several brands, and the physical game card.The test measured how long it took to load the game from each storage type, providing a clear look at which method is the fastest. (thanks to
4416Y)
- Internal Storage (256GB UFS): 16.60 seconds
- Sandisk SD Express (256GB):19.18 seconds
- Samsung SD Express (256GB): 19.41 seconds
- Lexar SD Express (1TB): 19.78 seconds
- Game Card: 24.75 seconds"