How to fix slow WI-FI on xUbuntu 14.04?

Question

WiFi

Good hour everyone! A question of the following nature - I installed xUbuntu 14.04 .. and problems with the Internet got out ... the connection keeps well (without interruptions) the problems are with the speed sooo slow, the most interesting thing is what happens as soon as the system boots for the first 20-30 seconds, it seems, quickly loads simple sites (it happens that it thinks for a long time, then it crashes to you and dumped the page) ... then wild brakes begin, and the more time passes after loading the OS, the more it slows down (checked - automatic updating is disabled, so it's not because of him )...
Torrents generally load at 17 kb / s, sometimes it jumps under 40 kb / s and this is always regardless of the time elapsed after loading the OS ...
There are 2 more laptops at home (Win7, Win8), a tablet and a phone everywhere the Internet is fast, so I don’t think it’s interference or the channel is clogged (I checked it - it sees only one neighboring point in the radius, I have the 1st channel they have the 3rd ), except that Ubuntu reacts somehow differently than Windows ...
=> in all cases, a DWA-140 wi-fi adapter and a Zyxel keenetik lite router are used.
What I tried:
1) Disabled IPv6
sudo gedit /etc/sysctl.conf
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
2) Tried this as well (although hh what does it mean - advised)
gksu gedit /etc/modprobe.d/ath9k.conf
inserted
options ath9k nohwcrypt = 1
3) Disabled IPv6 on all interfaces
sudo echo 1 > /proc/sys/net/ipv6/conf/all/disable_ipv6
4) installed wicd instead of network-manager
5) this link advises you to configure IPv4 manually, also tried
tssaltan.ru/498 .ubuntu-%D0%B8%D1%81%D0%BF%D1%80%D0...
In general, nothing helped.. if you need to drop something, write, I'll gladly do it..
dmesg - Checked , no driver errors found.
The output of some commands:
ping ya.ru
iwconfig
ifconfig
sudo lshw -C network
lspci -knn | grep "Net\|Eth" -A2
---------------------------------
Now I noticed the following: at the top, the network-manager icon itself shows the connection constantly and there are no messages about the break, but if you go to Edit, then against my connection in the Last Used column for some reason it says - 4 minutes ago, but the page is pulling albeit super slowly. Is that how it should be?
is it worth trying to put Mint on 14.04 or lower too, or will there be no difference? - if it's the drivers for the adapter, because that's what I think most of all.

Answer 1

Apparently, the wrong kernel module was loaded.
show lsmod and lsusb.
But before that, you can try this:
And add the lines

blacklist rt2800usb
blacklist rt2800lib
blacklist rt2x00usb
blacklist rt2x00lib