Well one way to check that is to unplug your router from the modem, and hook your computer directly to the modem for a minute or two and see what you can get.. ;-)
If I never get to fly online it will be worth it to not have to deal with what will no doubt happen if I touch any of those connections. Between Opt. Online's service and Linksys, I've got a "if it works, don't touch it!" situation here. The Evil Ones (router and modem) absolutely must not be disturbed! Been through many, many hours of grief when adding another computer, power interruptions, etc.