I'm using a Archer C6 as access point. The performance in 5Ghz wireless is not the expected, with other AP i got 600Mbps Down/UP. Using wire connection is about 750Mbps so the link speed seems not be the problem.
Of course with the stock firmware i got almost 550 Mbps (symmetric) with Open WRT i got about 290 download and 375 upload. WMM is enable. I think 300 Mbps in download stream is an significant difference even using an opensource driver.
Thanks, i have taken a look, seems the guilty is the opensource driver. I never play with the Openwrt source code, linux kernel is easy to compile and modify, maybe we have a chance to use the proprietary atheros driver while we have not performance improvements, of course i prefer to use the opensource first.