That seems odd. You'd expect that if the cpu is doing the encryption and can do 3GB/s for the internal disk then it can do the same for the external one and be limited by the USB or disk speed of 1 GB/s
If it’s a Mac then it’s not the CPU that’s doing the encryption for the internal drive. Macs have separate hardware for that, the CPU can’t even get the key.
That seems odd. You'd expect that if the cpu is doing the encryption and can do 3GB/s for the internal disk then it can do the same for the external one and be limited by the USB or disk speed of 1 GB/s
If it’s a Mac then it’s not the CPU that’s doing the encryption for the internal drive. Macs have separate hardware for that, the CPU can’t even get the key.