I recently moved to a bigger city, and of course the first thing that I setup was my internet connection. I’ve had the same ISP for a couple of years now, and they’ve been alright. I’ve noticed drops in service here and there but overall it was a tolerable experience. However, as soon as I started watching my online shows in the new place, I noticed some dramatic changes in my viewing experience. There were long periods of waiting for the shows to buffer, and I felt like I was relapsing to my younger days of dial-up. I got so frustrated one night I even tweeted about it:
Just took me two hours to watch a 1 hour movie. Why I’m leaving @coxcomm. — Krono$ (@SuperKronos) January 28, 2013
I finally decided to switch over and give DSL a shot, but I didn’t cancel my Cable. I figured I’d do a little testing and really see who was the better service after all. I put together a pretty extensive document of my results. You can find that document and all the data I captured and used in a link below. This blog post is a summary of what I found to be the important parts.
Before I continue there are a few things that I need to let you know. In all fairness to Cox (the cable provider), they did reach out to me via twitter to the frustration I vented above. They said that using a newer version of a cable modem (DOCSYS 3.0) would lead to faster speeds and better bandwidth, but I didn’t really want to spend the $60-$90 just for a study when I’m already committed to DSL. Perhaps if they’re willing to donate a new modem and a few weeks of free cable, I’ll redo the testing. CenturyLink (the DSL provider) become my new primary source of internet. I know that when testing like this, the test network shouldn’t be used during. However, my life is on the internet, and I wasn’t about to give it up just to avoid the randomized testing. So these results include daily usage on the DSL connection. The Cox cable line was untouched during testing with the exception of any Windows (or other installed apps) automatic updates. Finally, the results of this test may not be the same as what you experience. This is a quantitative and qualitative approach to testing in my geographical area. The Cable was a 25 Mbit/s advertised connection and DSL was a 12 Mbit/s advertised connection.
So here are a few interesting results:
During Peak Hours DSL outperforms Cable in Download Speeds
I considered peak hours to be between 17:00 and 23:00 local time or basically the hours that I’m most active online during the week. After testing I noticed that the download speeds were on average and consistently far better for DSL than that of Cable. Here’s the average speed over roughly two weeks. There’s a whole 2 Mbit/s speed difference between the two.
I put together a box plot that shows where roughly %50 of the values are for each. The DSL connection was more concentrated in one central area, and was faster than the Cable!
Finally I decided to put together a confidence interval where I could be %95 sure where the range of speed would be during those peak hours. This is what I found:
Not only was the interval smaller (less variation of the speeds during the hours), but it was overall faster than Cable! Before testing I assumed that Cable and DSL were going to be pretty close especially since the DSL connection was half the advertised speed as the Cable, but for the fact that DSL excelled beyond Cable blew my mind.
DSL Upload speeds aren’t speedy at all
One of the things that Cable did do well was in Upload speeds. Of course that’s because DSL only offered a 800 kBit/s up speed, but here’s a few graphs to show just how bad the comparison was:
This will lead to some bandwidth issues, especially if you’re gaming. Dropbox for iOS decided to start uploading my pictures while I was playing a game. This led to some pretty horrible ping times and me pulling out my hair wondering what was going on for about a 1/2 hour. The take away from this is, if you’re uploading a lot of data on a DSL connection, don’t play games while your at it.
Reliability and speed set aside: I still didn’t get 100% of my advertised speed
Neither Cox nor Century Link provided the full 100%
Cable’s 27% performance during peak hours is dismal and really unacceptable, especially since Cox did so much better according to the FCC’s national testing. DSL you’re not off the hook either. 71% is bad as well, just not as bad as Cable.
At the end of the day, how did I feel about the service?
Numbers are great, and they qualify what I as a customer feel, but in the end they really don’t matter. What matters most is whether or not I get frustrated with my current service. I have to say, that while DSL hasn’t given me the speeds that I expected and hoped for, the reliability has been a big plus. I’ve only noticed lags here and there, and I haven’t (yet) had to sit and wait for buffering that took just as long as the actual show that I was watching.