Massive Fps Drop on Forza 4 Online

Hi community and hopefully microsoft games support,
First of all My spec
GTX 1060 6 GB MSI
i7-8700 3.20 ghz
8 GB 3200 mhz ram
Msi b450 mobo
(ALL BOUGHT NEW AT August 2018)
Ok so the thing is I was playing at ULTRA settings without any single stutter or freezing 1 week ago.But now as today I can’t even play the game online on HIGH settings.I tried changing everything but still it didnt worked.I had the teredo error which prevented me from connected online 2 days ago.I fixed it.Now I don’t know if I have lag or something but the game is unplayable.I have 100 MB/S internet speed which is actually more than enough to play any online game.I am using ethernet cable so there can’t be any problem on connectivity.When on multi player all my PC Slows down.I can play PUBG and WOW at the same time with this pc but Can’t play horizon 4 alone which is weird.
In other games I have the lowest ping.But in this I think I have a more ping than my friends becasue they don’t have any issue.Please find me a fix I really like this game.