Low bandwidth and car freezes

I play the game since october with medium-high settings and i never had a problem with the it, but sice 2 weeks ago±, the car freezes sometimes, and when i can start moving again it has lost all speed. Sometimes a message that says low bandwidth appears in the top of the screen. I tried to low the graphics but it didn’t work. Does someone know what is going on?

My PC specs:
MSI B85-G43
I5-4460 (3.2GHz)
16Gb RAM (4x4 1600Mhz)
Gigabyte GTX960 4Gb (without overlock and updapted drivers, the temperature does not exceed 60ºC)
The game is installed on a SSD (550Mb of reading speed in sata 3 port with 6Gb/s sata wire)
For internet connection i use the ethernet port (100Mb/s with symmetrical connection)