SD cards are optimized for sequential IO (reading/writing photos, video, music). For an OS root partition, random IO is much more important for general use. If

SD cards are optimized for sequential IO (reading/writing photos, video, music). For an OS root partition, random IO is much more important for general use. If the root partition is mounted from an external USB drive with higher random 4K IOPS benchmarks, IO performance should be greatly improved.