Slow net conection,low quality in games after updating my N8010 to kitkat topic

Soo as the title say when i connect to wi fi net the connection is somehow slow i mean for example when i go in youtube and when i open a video it just loads to long no mater on what distance im from the modem the same goes for browsing by my ap Opera browser for android and also the download speed is slowed after the update and second problem is low quality in games for example i just downloaded asphalt 8 airborne on my tab and when i opend it the begining screen was in a black and white flag i mean i see the menus but the car in the background is like in a back and white flag on high visual quality but when i set it on low visual quality it fixes but its in low quality like in 480p XD ow and i almost forgot the batery somehow drains fast now soo this happends after i updated my Sasmung galaxy note 10.1 N8010 from 4.1.2 to kitkat 4.4.2 soo please help me :crying:
i didnt had does problems before btw

Im sorry for my poor english but i dont know what to do and IDK if there is another threed like myns if yes sorry again but i need help fast x<