When you say "checking speed", do you mean checking on nicehash website?
Nicehash gives a very high difficulty to miner due to large amount of miner rigs it connected. So the frequency of submitting found share to nicehash will be significantly lower than other pool (eg. sparkpool, f2pool).
And the hashrate calculated on nicehash based on how much share the miner submitted, could be very different from local hashrate, caused by the high difficulty.
I don't know how many 1080tis that you have, but if you got only 1 or 2 cards, then a relative big gap between nicehash reported hashrate and local hashrate could be normal, otherwise there's something wrong.