First of all, you simply may want to utilize 8 -15 Usenet connections at a time. If you are using far more, it could really reduce your downloading rates of speed. However, if you have a 100 Mbps connection it makes sense to use 50-60 connections. Generally slow Usenet downloads tend to be the result of a slow ISP, ISP throttling, home network issues, or possibly slow personal computer. Review these factors. You may want to try another Tier 1 Usenet provider, because they are apt to have quicker|more quickly speed compared to resellers.
To overcome slow speeds max out your connections to 10 and try using a different port. Giganews usenet video explains the benefits of changing the ports used for Usenet traffic and includes instructions for changing ports in various usenet news clients by Giganews.