As I managed to solve the problem before and after updates I started using latest kernel where the problem reveals again, I put my working config here
First - this one - sudo vim /etc/modprobe.d/iwlwifi-disable11n.conf having this one inside - options iwlwifi 11n_disable=0 is not affecting the wi-fi speed Secondly, I've installed 3.19 kernel - and it works for me GRUB config 1. Using grub-customizer, I've put 3.19 entry on top of menu list, to have it being run with just one 'enter' key 2. I've put here - sudo gedit /etc/default/grub the following - GRUB_DEFAULT="Ubuntu, with Linux 3.19.0-66-generic" the speed is good - about 36 MBit/second for upload/download both Hope it will help someone Note, that the latest (4.4.23 kernel) have buggy slow wi-fi driver(0.5, 2 MBit/second) -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1626283 Title: lenovo t420s very slow wifi after dist upgrade 14-16 Status in linux package in Ubuntu: Confirmed Bug description: it is not more than 2 mbit\s for the moment - before upgrade it works well - about 40-50 mbit\s. it is not ISP issue other devices works fast at my wifi network ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: ubuntu-release-upgrader-core 1:16.04.16 ProcVersionSignature: Ubuntu 4.4.0-38.57-generic 4.4.19 Uname: Linux 4.4.0-38-generic x86_64 ApportVersion: 2.20.1-0ubuntu2.1 Architecture: amd64 CrashDB: ubuntu CurrentDesktop: Unity Date: Thu Sep 22 00:29:18 2016 InstallationDate: Installed on 2015-12-17 (279 days ago) InstallationMedia: Ubuntu 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805) PackageArchitecture: all SourcePackage: ubuntu-release-upgrader Symptom: dist-upgrade UpgradeStatus: Upgraded to xenial on 2016-08-17 (35 days ago) VarLogDistupgradeTermlog: To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1626283/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
