The actual frequency is 850mhz, so the formula is:
gddr5: 850 mhz * 128 bit / 8 bit * 4 (gddr5) = 54,400
I have this card. I got it because It uses only ~55watts @ load (i measure it. yes you can measure it even if it does not have a pcie power connector) and performs Good.
Guy's not...