Like a lag issue.

So there is one problem with my wow client.When i do pvp or even pve i have a huge delay( like i stun a player and it keeps going for 2-3 second and then he stops moving ) about 2-3seconds ( but i don't have internet problems at all ).
I don't know what is it all about since i got new pc ( more powerful than the last one i had ) and i got win7 64bit on it. I tried reinstalling it,deleting all kind of files,download it 3-4 times and it still have the same issue over and over again. I even tried to run the program in compatibility mode for Windows XP (SP3) since the previous pc was running on it ( then was no issues at all ) but it still didn't worked.

If anyone out there reading this might knows what the issue might be or could salve the problem , i would be very thankful.

Best regards, Goran.