I must say I go get occasional stuttering or significantly lower framerates - but only in busy network instances.
Worst I've ever seen was in a High-Intensity Conflict zone (which also had tons of bugged guided Missiles never de-spawning).
There it got so bad that it became unplayable sometimes, incl. sound stuttering.
Seems to me the increased pairing of P2P candidates for any Network Instance came with a price of these framerate drops, as operating with only very few Players or alone still yields a constant 60fps (VSync On) no matter what.
Not sure why the framerate is coupled to the network sync (if my observation is correct) - IMHO that would be quite unusual and counterproductive to a smooth gameplay experience.
I'm afraid you're right. My laptop has solid performance at my home connection, but due to the XMas holidays and work I've been in two/three different environments. Results pretty simple:
Home - 60FPS, all good, no problems
Site 1 - frames all over the place depending on wireless signal
Site 2 - frames all over the place depending on wireless, even with graphics quality reduced to lo and screen resolution cut
I've no idea why the networking code would impact FPS esp. as the bandwidth requirements seem low and none of the sites I use have bad bandwidth (am on 4Mbit/s up/down at the moment for example) with a ping of 1ms -no that's no typo, it's 1ms to a local server in-country) but my location def. affects performance. I guess the distance to the respective Amazon servers make the difference.