in my tests, 0780 & 4f81 yielded the same result - so I think they are both very close, if not 400mhz
I can confirm that my overnight test seems to be a success... averaging 197GH @ .59% HW ... which is higher than the 375mhz setting, but lower than 400mhz
I dont know what the exact equation is for figuring out hashrate based on clock but the numbers match up with 512*mhz = mh/s
Based on that equation, 5e82 seems to clock in right around 384mhz
Also, if someone wants to experiment w/ the xx83 ranges ... I imagine the values will start in the 6x83...
I now figure out the HEX.
400MHz = 0780, = 4F81 and also = 5F82, but 0780 and 4F81 are preferable,
as it comes with the config and don't know whether 5F82 will do any harm.
387.5 MHz = 4F01 and also = 5E82, you may try 4F01, it should be OK (may give different HW error, but same MHz)
So I tried something like 412.5 MHz '5001', and again very high HW errors 4.x% (~ 425MHz's HW error).
I think I have good-enough cooling, it might be the hardware stuff for the error, so I went back to 400MHz then.
Refer to the manual, what I can tell you is that the freq_value ends with '2' should not be over 250MHz.
So you'd better use the freq_value ends with '0' or '1' instead.
For freq_value ends with '3', you won't get any better result than 400MHz, and also quite risky for the hardware.
FYI, also 6082 = 412.5MHz and 6002 = 406.25MHz (Risky, it's over 250MHz)
I have no responsibility for any damages for any experiments.