edge router x -slow down speed

hii..

i am new with edge router x

my speed is 100/2 Mb connect on eth4--dhcp --cable modem.

my config is wan+2lan-config >eth4-wan >eth0,2,3>switch 192.168.1.0/24 >eth1-config lan 2-192.168.2.2

my problem with speed down my speed not get then 60-80 Mb

no qos ,config with basic rull ,i try eth0/4 config wan and eth1 lan only but no change the speed

before i had tplink 1043nd and i get 100/2 mb down/upload

i do not what to do next

thank you.