Beware that if you're not getting power explicitly on pin 20 it means the card is working essentially through unintended paths and/or leakage and that might very well lead to data corruption and even loss of the cf card.
I had this happen to me when I plugged an adapter to a controller card and forgot to power it explicitly and it borked the cf card.
If you want things to be neater either add power to pin 20 (if it's physically on the motherboard connector) or you can bring 5V from any other header on the board like for example USB or IRdA, you just need a single female-female dupont cable (ground is already well connected)