Cisco 3640 WIC-1ADSL Speed Troubleshooting
Cisco 3640 and wic-1adsl speed problems
Historical platform note (updated July 2026): This Cisco 3640/WIC-1ADSL investigation concerns retired equipment. Use current platform telemetry and vendor documentation when diagnosing modern DSL or WAN performance.
I recently decided to plug my wic-1adsl card into a 3640 router because my 2620 had a power supply failure. I noticed that the cisco 3640 ran very slow, and speed tests topped out at 2.6mbps downlink speeds. For a while I couldn’t figure out why a router that is faster with more memory would run slower than my 2620 router. I later discovered the reason for the slowness was because of a bandwidth limit on the nm-1fe1r2w card I was using to give me wic slots.