Gigabit doesn't work on Intel I219-V

Hi all. Few days ago I bought the motherboard MSI Night Elf (network adapter Intel I219-V).

I Have a problem with gigabit internet. It doesn't work. In properients i see 1 GBPS, but on speedtest.net i see only 100 mpbs.

It's not a problem with cable or router, because in the past i had not problem with it (before that i have a motherboard ASUS P5Q3 and saw real speed 800 mbps).

I hope to solve this problem and hope for your help.

Thanks a lot!