Doesn't it run over a single TCP connection in all cases, unless you manually launch multiple and manually load-balance your clients across is? As in, it won't/can't open a new TCP connection when you open a new connection in the SOCKS proxy or port forward. They'll all share one head-of-line and block each other

Not that I've ever noticed this being an issue (no matter how much we complain, internet here is pretty decent)

Edit: seeing as someone downvoted your hour-old comment just as I was adding this first reply, I guess maybe they 'voted to disagree'... Would be nice if the person would comment. It wasn't me anyway