If you are experiencing slow download speeds and fast upload speeds using a wireless Linksys (Cisco) E2100 V2.0.01 here is a possible solution. Also applicable with othe Linksys (Cisco) models. In this scenario, ISP was comcast
1. Log in to Linksys device using default IP address 192.168.1.1 or other if different.
2. Click on Applications & Gaming Tab
3. Click on QoS submenu
4. Disable WMM Support, click save.
5. You should experience normal speeds.