Banana Pi R2 Slow Ethernet Speed

I installed snapshot-openwrt on the device nand chip without any problem. but there is a strange situation. I am reaching a maximum speed of 10mbps on the speedtest.com, fast.com etc. My internet speed is 100mbps. There seems to be a problem with ethernet but I don't know what to do. I've tried dhcp and pppoe modes, there was no change. I wonder if you have a problem with openwrt?