WRT1900ACS vs R7800 network speed Raspberry Pi

[EYEREX]

Hello i have a WRT1900ACS and R7800 and wondered why the R7800 gives me slower and fluctuating transfer speed to a Raspberry Pi over WiFi
I know any drives connected to the Pi are never going to be that fast but the WRT1900ACS gives me a stable 11mbs up and down but the R7800 will start at 10mbs then drop off to about 4mbs with uploads to drives connected to Pi, strangely download file transfers from the drives to PC via wifi are a stable 11mbs

Using DD-WRT
Have tested Kong and Brainslayer builds which act the same plus tried Kongs OpenWRT build

 

[Avalon]

The answer is obvious - different hardware/drivers on the router side - surely the more important question is why wouldn’t you just move the pi set-up to a location you could cable it directly and not be running via Wi-Fi, it’s not like a pi isn’t easily moved and the likely speed improvements are significant.