Region : UnitedStates

Model : Archer C7

Hardware Version : Not Clear

Firmware Version : 3.15.1 Build 141204 Rel.39308n

ISP :

Hello! i have windows 8.1 64bit
Router Tpl Ac1750 W/db Usb Archer C7 v1.1
and TP-LINK Archer T4U USB 3.0


my velocity of internet is
50Mbps download
10Mbps upload

actually i use wifi ac of wifi card: TP-LINK Archer T4U USB 3.0
and my download with this wifi card is 6.5MB/s with 5ghz wifi,
but when i upload a file, it upload for 250kb/s, and my velocity of upload is 1MB/s,
in the option of T4U USB in windows, i have

enable adaptivity - disable
ldpccap - VHT LDCP TX|RX & HT LDCP TX|RX
qos support - support qos
stbcCap - VHT STBC TX|RX & HT STBC TX|RX
USB SF Mode - disable
USB Switch Mode - force mode usb 3.0
Wifi Config - Performance (the another option is wifi)
Wireless Mode - IEEE 802.11ac (the another options are other mode, but i've changed it becouse download velocity work better)

if i connect pc via cable to router, the upload velocity is 1MB/s , the problem is in wifi

if i try with another wifi card but with wifi n (like this [CODE]http://www.amazon.com/Thailand-Sellers-Wireless-lifetime-Warranty/dp/B00MOBHL5A/ref=sr_1_4?s=electronics&ie=UTF8&qid=1422677816&sr=1-4&keywords=Tenda+150Mbps+Wireless+PICO+USB[/CODE] ) , do the same, the download velocity is correct but download is 250Kb/s

today i update firmware of router to
3.15.1 Build 141204 Rel.39308n , but didn't fix problem

any suggestion? how can i fix it?
thanks