It could also be the signal strength. This could be either do to poor cabling in your house or upstream. The cable company can likely tell you if you are getting sufficient signal just from looking at your account.
If it is upstream... it's up to them to fix it. If it is in your house, it's probably cheaper for you to track it down and fix it yourself.
The cable company has been bugging us a while about getting new equipment so we can advantage of the faster upload/download speeds. They want us to lease equipment from them so we've been ignoring them. We stream tv (hulu plus) but don't download movies or anything where the speed has been an issue.
How would I track it down in my house if that's the case? The prior owner was a bit of a mad computer wizard with cables running every which way in the walkout basement (where our modem/router is) that we largely ignore. A computer friend of mine's eyes lit up when he saw it and he started talking about coaxial cables that are 4 or 6? can't really remember, but he seemed to like it (although it could be better).
Signal strength is easy to screw up over time.
My wild guess of likely culprits:
* bad or out of spec cable (not RG6).
* bad job of splicing end connectors at the end of cable
* cables run outside and subject to sun/rain/rodents/etc (or have nails through them)
* a bad or lossy cable splitter
* a connection that just isn't screwed down tight
I know cable companies are hated... but they do have some instrumentation here to at least test stuff... find out if it is their fault first. They an also hook up a meter and see what the loss is right there at the modem. (No idea if they'll charge for testing or not.)
If it were happening all the time, I'd take the cable modem out to the d-marc (where it comes into the house) and hook it in there and see what happens. But with intermittent issues, that's not so easy.
But yes, a new modem is cheap. And a docsis 3 modem will get you more speed (if you so desire). I know where I live, the smallest plan they sell is 50mb downstream. But it requires a docsis 3 modem to do it. (In other words, here you'd be getting less speed and paying the same price.)