As I said. DON'T go full 400Hz. Look at mine it hits 200GH/s but low Hardware Error % and good Temp and don't for get the Heatsinks for the Converters (Total of 8 )
may I ask what hex code you're using for 393 MHZ ?
I tried '5f82' but got 2.5% on many of my machines, but going for 387MHZ using hex code '5e82' seems to give me 0.5% error with 3 Ghz less total hash output. This seems to be consistent across atleast 10 of my S1 ants