Netflow CPU usage is too high

Hi, i have problem with netflow… my machine is dell R220 4x Xeon 3,4GHz and traffic + - 1,5Gbit/s
cpu usage with netflow is 60%
without netflow only 10%

here is my config
vyos@NAT1# show system flow-accounting
interface eth2.1705
netflow {
engine-id 100
sampling-rate 500
server 37.221.X.X {
port XXXX
}
timeout {
expiry-interval 15
flow-generic 3600
icmp 300
max-active-life 604800
tcp-fin 300
tcp-generic 3600
tcp-rst 120
udp 300
}
version 9
}
[edit]

where is problem? is this normal? We have Mikrotik CCR before and netflow cpu usage was under 5%
thak for reply
Bohous

which version of VyOS?

Version is stable 1.1.8

Do sampling rate and buffer size settings have any effect on it?

cpu usage is higher… this config is after many tests best, but still not OK.

Hi. I also encountered high CPU utilization when enabling flow-accounting. Did you solve this problem?

no, we have the same problem on brocade vrouter … we solved it by mirroring port to flowmon