we have ptp link,

this is picture from ap-bridge, 10.0.0.2 is PC behind station, traffic are routing

ap ------- station ------ PC(10.0.0.2)

same ping from : PC --- ap --- station --- PC(10.0.0.2)
and same ping with 4/4-mbps, 1000/1000-p/s

link have good signal , CCQ are 100% , nstreame=exact size , frame 4000, freq 5ghz ch-20mhz
link are 1km
CPU on ap and station are 20-30 % max.

why ping are no stable ?

is this maybe hardware problem ?

try lowering your tx power. that 60 db signal to noise ratio is weird. try with 10 db on tx power if you say it's a 1 km link and see what happens.

try 10, 6, 1 ... not stable , on 1 signal is -59 , signaltonoise are 44

card for this link are on same IRQ with USB (we not used USB), can this be problem ?
on the AP side we have intel 440BX cip P3 , maybe this ?

can the card be problem ? ... on AP side are some card on 5ghz with no vendor on it.
by MAC vendor are "gemtek technology co., ltd."

try other channels. try switching Band to 5ghz-turbo (if it's supported) or 5GHz-10MHz or 5GHz-5MHz, but I still think your problem is that you have more power than you need.

I put 5ghz-turbo , but only 3 chanel

5210Mhz - same thing 1-30ms (P Troughtput 30mbps) ?!
5250Mhz - ping 1-3ms (P Troughtput 55mbps)
5290Mhz - not try

,can turbo-mode work on any extra-chanel ?

I put 5ghz-turbo , but only 3 chanel

5210Mhz - same thing 1-30ms (P Troughtput 30mbps) ?!
5250Mhz - ping 1-3ms (P Troughtput 55mbps)
5290Mhz - not try

,can turbo-mode work on any extra-chanel ?

switch to country that supports more turbo channels.
try decreasing the tx-power to 12dBm / link -65/-65 is good enough for 60Mbps and <1 ping /
put framer-policy to best-fit and 3200.

turbo mode , txpower=12dBm ...

this is good.

can turbo mode work with any extrachannel ?

btw, which country have most channel in turbo mode ?