Good signal to noise, but poor CCQ and poor perforance

I have a short link (500m) with Signal about -58dB and Signal to Noise over 44 dB, but Tx CCQ is arround 10% only and P Throughput less then 1M.

Both router are in ver 3.15, working at 5GHz-10MHz with freq=5775MHz

What can be the cause of so poor performance/CCQ with 40dB usable signal ?

Thanks,

Alexander

Interference. You should also turn your power down until you get somewhere around -64 on both ends.