Asus rt ac58u vs archer c7

hey guys
I'm planning to get a new router and was wondering which one will give better data transfer speed over 5ghz from my NAS.
Currently I'm using this dir868l from dlink but it let's freezing all of a sudden so I'm planning to get a new router.
any suggestions will be appreciated.

The RT-AC58u with its ipq4018 quadcore SoC should win hands down, but the ZyXEL nbg6617 might be a better idea (twice the RAM, easier to flash).

ohh and here i thought c7 would be faster as it is rated for better speeds (at least in theory). unfortunately that zyxel router isn't available here any other recommendations, any other brand except d-link around this price bracket.