Windows 7: rFactor huge ping

Game runs fine, but when i'm trying to play online there is huge ping about 600-800 ms. The most interesting part is that, when press button "ping" it shows me about 80 ms, than i ask others players, in the same server what is my ping, they tell me that it is about 600!!! After connection to server game shows me other players ping about 150 ms, then gradually it begins to decrease down till 0 and than gradually increases to ~450. After this trick, game constantly synchronizes. So, can't understand anything . Have tried many methods written in this forum: audio configurations, net mesh, disable ipv6, multimedia sevices and so on. Finally installed win xp in the same pc. Game runs fine without any huge pings about 80-100 ms. Any ideas?

If the game is older than Win 7, it might not support it, and thus act in unpredictable ways. Im sorry, thats all i can say. I was going to recommend disableing ipv6, but you've tried it, so no use...

There is some weirdness. There are many people who play it on win 7 and have no such problems. Other games are running fine on online.

i have the same problem it dows it on gtr2 aswell cant solve it aswell