On a good day my home modem provides 3Mbit down and 384Kbit up. Each graph represents 2 minutes of traffic between my router and modem. In both cases multiple users were connected to the web, running chat programs, streaming media, etc.
Sample 1: Uploading large file to 8svn and attempting to download a large file from a fast website. Upload bandwidth is maxed out and the download speeds are slow. Latency is very high and makes typing in ssh sessions nearly impossible. Ouch.
Sample 2: QoS is enabled in the router and a large file is being uploaded to 8svn on port 8443. Upload bandwidth is maxed out and full-speed downloads are possible. Web browsing is snappy and ssh sessions are responsive. Excellent!
Original Post: Port 8443 = Simple QoS Management