Phone Slows down Internet

[Konn]

Hello,

My Sony Xperia Z1 has been acting up lately. 

Everytime I connect it to my WiFi it slows it down dramatically, from 30 ping to 50-200ping~ (unstable).

I have turned off auto sync and auto back up on the phone but it keeps happening. 

I know it's the phone because once I turn off its WiFi, internet speeds go back to normal.

I'm sure I have nothing downloading in the background as well.

Can anyone help?

Thanks.

[_alexdon_]

Do you have any task killers or battery savers?They usually slow down the phone.Also antivirus does it.

[nickthenightfly]

It happens even with my z3c. From 2 weeks ago all my internet connection was going very slow. Also on my mac. After a lot of struggling, my internet provider found that the mobile phone when connected at the wifi, was uploading a lot lowering dramatically the download speed. Most probably the guilty is an app. I think is one of these 2: auto sync or antivirus...... Still unsure which one

[Curnow1]

Go to wifi and go to advanced settings then don't turn off wifi optimization 

Settings > Wifi > advanced > wifi optimization unticked