Does the RWIN affect pings or packet loss?
No, the RWIN does not affect your pings. Ping is latency on the Net, and not your computer, therefore it can not be lowered. Latency changes every second on the Net, with the pulse of it’s many users. If your line is already lossy, a higher RWIN from Windows default (ME/2K/XP: 17520, 9x: 8760), then it may cause packet loss.