I'll preface this by saying, I don't expect a resolution, but would love one. This issue only seems to effect 1 game, on my PC. PS5, PS4, other pc games, are all fine. 

Was all fine for maybe 9 months before I had this issue. 

Playing Battlefield 2042, I get lots of lag spikes. They appear as a 1 second pause, FPS drops by about 30, but feels like the whole game froze for a second. Using the network graph in game, I can see my Time Nudge spikes higher than my Client Frame Time or Server Frame Time when this happens. 

I have a Virgin SH 3 (250mb, 25-30ms ping) in modem mode, into an M5, into a switch. Cable from switch goes upstairs into another M5, into another switch. 

I have tried everything PC side, reinstalled all drivers, game etc. The reason I am here, is because if I connect from SH3 to switch, to PC, its fine, these spikes don't happen at all. I can play for hours and not get 1. Go back to using the M5, I get 5-10 a game. Same cables, same pc, same settings etc. I have done this repeatedly, it is definitely related to the M5s being involved. 

I have tried setting my PC in the app as priority, I don't have any network protection settings on in the app. It has doen this over multiple firmware versions. Ive just seen there is 1.6.5 available, so I will try that. 

It seems there is something with the way the data is handled, specifically with this game. 

For reference cpu is 5900X, gpu is 3080. 32gb ram, Gen 4 NVME SSD. I cap fps to 141, if I uncap will hit 160-170. PC is plenty capable.