My WiFi ran flawlessly for a good 5 month and it started to have serious lag spikes 2-3 weeks ago. I encountered shuttering/ rubber banding lag in Counter-Strike and unstable pings in League, from 35 ms to 150-200 ms and then drops back to 35 after a few seconds.
I've been finding the solution for days and I have came up with some conclusion. First of all I am living with 2 flatmates and usually about 7 devices are connecting to the router at the same time. I thought that could be the cause of it therefore I asked them to turn off all the connections for me to test. Sadly problem still exist. I have also asked one of my flatmate to perform a League game test and his pings had ran smoothly throughout the entire game. Therefore I have narrowed down the cause of problem to my own PC.
I have tried changing the router channel to 1,6,11 and the lag spikes still exist. Here is my result of tracert google.com: https://i.imgur.com/csot902.jpg
My CPU usage is normal, and I have also tried WLAN optimizer to turn off the regular WiFi background scan. I have also got rid of 'utorrentie.exe' recently- A while ago my Norton anti-virus warns me every time I open my BitTorrent application and have this pop-up window tells me that it deleted 'utorrentie.exe' because it's harmful. I know it is a malware that will reinstall itself and I thought the reinstall-delete progress loop between the anti-virus and the malware could cause lag spikes. But I have now got rid of it by creating a text file with the name 'utorrentie.exe' and saved as 'all file' and set the permission to nobody, not even the admin, so it can't reinstall itself.
Sorry for such a long boring post and I thank you if you are still reading up to this point. I will be grateful if anybody comes up with new potential solutions, because I have tried most of the troubleshoot methods and I am currently stuck in this!
Thanks again for reading this.