First mining :dgb with gtx770 only 50mh/s is it ok???

[3dee]

?Hello,

I'm fully noob to mining. I just started a days ago.
I'm using cc mining on TBF pool so any advices are highly apprechiated.

So the main question is this normal that I have only 50MH/s with my gtx770?
Should I change anything to make mining faster and increase the performance?

Currently I set the difficulty to 0.5
allgorithm is sklein.

Also I wondering if axist any USB miner for DGB?

Thank you for your prompt help!!