Would love to add a s9i but they auto-tune from what I've read, little user control
My V9 is most likely a rebranded S7 and more expensive to run
However, I've under clocked it down to 300mhz and it runs 8 ~ 10 C cooler in the garage (2T/hs)
Crazy but I'm going with a second one to add to the cKpool
Prefer to be in control even with the higher operating cost

My S9is (14T Models) do not allow any frequency or fan speed manual adjustments.
The miner configuration page only shows pool configuration options. These miners are latest
July 1 batch. Could be the earlier batches allowed more manual configurations. They're great miners,
however, and the 14T models save more energy than the other S9i models according to YT reviews.
I don't blame bitmain for taking away the manual configurations. So many people are overclocking
their miners and then probably try to get warranty work on them after they set their miner back to default,
thus deleting all logs that show they were overclocked. I like what Halong does with their T1 configuration
options: "Efficiency, Balanced, Factory, and Performance." No chance to void the warranty but some control over the miner.