Anyone using 802.11 AC wifi ?

Hi
Currently using a Cisco EA6500 router with an Asus AC66 pci card in my desktop pc, and both of these support wifi AC on 5ghz with speeds of up to 1.3 Gbps. However my desktop can 'only' connect at 600 mbps. Obviously i'm aware that 1.3 Gbps will only be achieved in ideal conditions and even then its a theoretical max as real world speeds will be lower. My desktop pc is upstairs, router is downstairs and straight line distance is ~ 5m but walls are wafer thin. Tried forcing the router to use 80 mhz channel width and played around with different channels but still cannot get more than 600 mbps. Is this the best i can hope for? Previously i was getting 450 mbps on wifi N again on 5ghz.
Cheers

The card might support 1.3 Gbps but will the PC?

I have a Gb lan but can only achieve 600-700 Mbps because of hardware constraints behind the network card.


Also, what is in the floor or walls? Some plasterboards are foil backed - a great reflector,