Default 802.11ac on gt-i9500

Has anybody seen issues with the 802.11ac network on the s4 gt-i9500. I can get 100% signal throughout my home but I am only able to browse when I am in front of my netgear r7000 router where I get 120mbps connection speed.

I can't browse from the bedroom upstairs although I get 100% signal but only 6mbps connection speed.
My nexus 10 which doesn't have 802.11ac has better connection in the bedroom.

Please let me know if its the problem with the phone and not the router.

Sent from my GT-I9500 using XDA Premium 4 mobile app