As the slowest link in the chain.
You're not making a direct connection to Cnet's servers, your connection is being routed through who knows how many different routers along the way, each of which can have load values ranging from you being the only one connected at the moment, to being completely overloaded. A single slow router along the path will slow things down by some value that is impossible to predict.
Secondly, you're on a cable connection. Cable is a SHARED bandwidth system. You share a set amount of bandwidth, with everyone on your particular neighborhood hub set up by the cable company. One or two little kids who don't know any better, or otherwise inconsiderate people, can destroy your download performance. That's just a fact of life with cable Internet, there's nothing you can do to change it.
I'd say that 92K/s is actually pretty good. That's close to 1Mbps. To make the math easy, and account for overhead, you can just figure that every 100K/s is equal to 1Mbps. So you're looking at a top speed of around 300K/s with your connection, under ideal circumstances. You're downloading at roughly 1/3 of your total potential capacity, which is quite good for getting something off the Internet.
You should be pleased with the speeds you're getting. There are a lot of people who'd kill for those kinds of download speeds.