Above Comcast Speed Test is the best result so far for the 5341. I do notice an issue where the modem slowly ramping up on bandwidth. It starts at 0 where the SB6120 starts are 40Mbs. Despite the slow bandwidth start, it makes up for it in the end. I do notice the downstream SNR is better on the 5341 than the SB6120.
Not sure if there are issues with the new 5341J firmware since Comcast automatically updated to the latest.
The SB6120 has higher bandwidth spikes but the 5341J is more consistent.
However the 5341 "seems" faster and with the extra bandwidth, it can return higher speed test results as the test ends. For example 52-55 for the 6120 and 53-57 for the 5341. However the data reveals the SB6120 maintaining a route consistency where the extra pipes plugged into the 5341 maybe causes the route consistency to drop but getting more bandwidth.
So.....overall a little shaky but more bandwidth from a 8x4 setup versus 4x4 as expected.