Default Wifi issue

after the 4.4 upgrade I noticed that my WiFi was significantly (%90) slower
Before kitkat wifi speed was 35 to 40 Mbps max,,After the kitkat wifi speed is 3/5 mbps almost %90 down I try everything reseting the phone,resetting the fibre optic modem nothing works
But i try Ookla speed test on galaxy express 2 connected the same network and speed was 38 mbps
Is this right ?