how can you tell network hashrate ?
and how can you find who owns much/maximum hashrate ?
The highest spec GPU at the time was 700MH
was that single gpu or multiple gpus ?
The diff gives you an indirect estimate of the network hashrate.
This command also estimates it:
bitcoin-cli getnetworkhashps
1.16286092598526e+19
Back then it was public knowledge who was mining what where. Things have become much more secretive since.
The 7970 back then peaked at 720MH (per GPU).