Different implementation of blockchain can have different speeds. It all depends on the consensus algorithm used.
Bitcoin uses proof of work consensus algorithm.. Every node in the bitcoin network has to find a nonce to create a block with the right hash.. There are no shortcuts in this method, the nodes have to check for each and every possible solution and it takes time. The average time for block creation in bitcoin network in 10 mins..
Nubits use proof of stake consensus algorithm.. In proof of stake, the miner is chosen depending on the amount of tokens he deposits as "stake".. Higher the stake, higher the chances of becoming a miner.. Proof of stake takes less time than proof of work..
Hence, Nubits are faster than Bitcoin..