Here is potential fix if you are experiencing slow USENET download speeds using SSL encryption and you are using port 563:
switch to port 443
Specific scenario: I have a backup Hughesnet satellite internet system that uses one of their slowest plans. It used to get 120kbs+ download speeds but recently it seemed to be throttled to about 10-14kbs. I tried adjusting the number of connections from 3 up to 6 but that didn’t help. However, after switching from port 563 to port 443 my download speeds were back to normal!
NOTE: this situation is likely caused by Hughesnet throttling traffic on port 563, which is the standard port for USENET encrypted traffic. Thankfully, port 443 is generally for encrypted HTTP (HTTPS) connections and no ISP is likely to throttle that port much as it would affect all sorts of users visiting all sorts of sites (Gmail, Amazon, etc.)
Thankfully, one of the most popular usenet hosting providers (Giganews) supports secure connections via port 443
Real world results: my download speeds increased 10x just with this simple trick! Here’s hoping it helps you too if you are experiencing slow download speeds using SABnzbd or other NZB clients