The SB6141 has problems. There is no explanation around it. You can talk about tests, tunneling, 7 layers, be a Meastro at networking architect, write lengthy explanations, disconnect from gamer's claims, etc. It has been said before elsewhere and even in this thread that the modem suffers issues. I've played different servers with different games over the past 8 or more years with these puma chips. 5+ years with UT3 with the 6121 and the 6141, from servers in Chicago, the East Coast official Epic Servers, to UT4 with servers in Atlanta. That's just two games. The RO:Rising Storm/Red Orchestra with servers all over, to Rising Storm Vietnam and servers all over, also. I even noticed it in CS:GO recently, and they even have special networking to help improve the game. I even moved once. In just those games mentioned the same issue comes up with the 6141 & 6121 no matter what. Consistent Random stuttering.
If I was unsure and had doubts I'd listen but there is absolutely no doubt that there is stuttering with the 6121 and 6141