I had a 8150 until recently so I know that line of chips can pull APB with no problems. The 8350 is the same except around 200mhz faster i believe? Anyway, have you looked at your temps while playing? Or maybe tested against another game to see if it happens there as well? I know it shouldn't be hardware but i'm just trying to rule that out. If it happens around the same time each run then it could very well be some obscure hardware-related thing.
Q: Does it happen around the same amount of playtime or match time? As in, if you join the game half way into the match, does it immediately do the lag thing? Or do you have to actually play for 15 mins? If you suffer through to the end, does it to fine at the beginning of the next match or remain slow?