Internet speed limits at 2mbps (i have 10mbps line) - R6220 - 1.1.0.80 firmware

Router model - R6220 and firmware version is - 1.1.0.80 

Hello guys,
i have 10 Mbps internet connection and um getting 10 Mbps over direct LAN to my pc but when i tried to connect via my R6220 it limits to 2 Mbps(download- over LAN and WIFI both) and upload remains same as my original speed. why this is happening with me ?? it was okay 3 days before :( 

i tried to factory reset and downgraded to old firmware version to see the difference but still same results.