Thanks for all the awesome comments
I never tested the card cold without the power card but I gained about 35mhz testing on water. I had a really bad mount for this session, I hope next time the card will go much higher!
I think it might go higher with a better pot and more Vcore. I tested 68/61 @1.85v, but would not pass at that speed. It seems there is no scaling going from 4/4 to 2/2 with this L640 CPU, so next run will be 4/4.