A Short Story
There is an Antminer server farm I provide support for with over 100 BC servers—mainly S9 and T9 models. There are three specific S9 miners that are side by side right next to each other on the rack which continually show lower than normal hash rate in Slushpool.
When I check these servers in Slushpool they all three fluctuate often ranging from 11-13 TH/s but the web interface and command line RT and AVG hash rates are always normal with no fluctuation. Every time I check Slushpool though, it's almost always lower than normal and I've checked up to nearly a hundred times in one day just to ensure I was being thorough.
Question
Is there anything common or something someone else determined that could cause a miner hash rate to always show lower in Slushpool than what it shows from the local server?
Notes
I've checked both command line and web interface on all these and see the same thing; normal realtime and normal average always every time I check but with Slushpool, it almost always shows it is hashing lower by 1 or 2 TH/s.
Typically when other miners in this farm have a lower than normal Slushpool hash rate, the local servers have a value that correlates much closer to that hash rate so I'm trying to understand if there's something I don't understand here which may explain this.