Hello aspirant!
Hope you are doing well!

The cut-offs keep changing yearly depending on total candidates appearing for examination, level of complexity of question paper and other factors. Hence to predict the cut-off accurately is difficult.
But you can consider previous years cut-off and take them into reference
SBI Clerk 2016 Mains Cut-off- 62.50
SBI Clerk 2018 Mains Cut-off- 66.2

So, most probably sbi mains cutoff for dxs in Bihar will be nearly around- 65-70%
Candidates are requested to stay updated with the website to check the official SBI Clerk Cut off 2020 . It is released along with the result.
Hope this helps!