Was wondering if it has been tested whether there are any differences between retail physical cards and having a game on a sd card. I bought a UHS-3 SD card and was wondering if the N3DS is able to take advantage of the rw speeds.
UHS-3 is overkill, but a decent card does have benefits.
I had a Sandisk Ultra 32GB that was horribly slow when installing CIAs, and have since started using Samsung EVO cards with noticeably better results. You are limited by the 3DS/Reader so the ceiling is should be pretty low, but you can definitely do badly.
I got a Samsung 64 GB Evo MicroSDXC UHS-I Grade 1 Class 10 - and it's plenty fast in my N3DS. Games that don't cap their save speeds and loading times zip along really fast. (although the Clock+L2 patches might be helping with that)