Standard SD card and Micro SD card with adapter; same speed?
Solution 1:
The adapter is basically just a bunch of wires; they use the same signaling. The class of the device will determine the speed, not the adapter.
Solution 2:
As far as my experience goes, there's no difference between using an SD card vs a micro SD card.
I've even booted full linux distributions from a micro-sd card (8GB) with a SD adapter