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There are a lot of factors involved in downloading a file to your computer. When adding it up, however, you need to know the difference between a bit and a byte.
Hi Leo, I get a pretty good download speed of around 14mb/s. Yet when I go to download for example, a 14 MB file, why does it take so much longer than just a second? Yours confusedly.
In this excerpt from Answercast #37, I look at download speeds and methods for determining how fast a file should download.
There's definitely a confusion here, absolutely.
The speed that your internet connection is measured in is in megabits per second. So 14 Mbs (usually lower case "b") is a 14-megabit connection.
The file that you're downloading is a 14-MB file ("megabyte", normally that's with an uppercase "B").
The difference, of course, is a factor of eight. There are 8 bits to a byte and thus, one would expect a 14 megabyte file to take eight times longer than downloading 14 megabits.
So, it's not gonna be a second. At best (and I do mean "at best"), it's going to be something like eight seconds.
Now, it's not even going to be eight seconds; and that's basically because nothing is perfect. A 14-megabit connection may, in fact at times, actually download 14 megabits per second – but there's more to your data than just the data:
There's lots of overhead in the protocol;
There's error checking information that is added to the data;
There are headers;
There's block information;
There's destination information that says, "This packet of data is intended to go to this particular computer."
A good rule of thumb that I always use is if I'm getting for a download something on the order of 80% of my rated speed, I'm pretty darned happy.
Sometimes it can go faster; sometimes it will be much slower, especially if there's other things going on online at the time.
In a case like what you're experiencing, downloading 14 megabytes on a 14 megabit connection, I would expect it to take somewhere between (I don't know...) 12 and 15 seconds.
In other words, definitely not one second.
Unfortunately, not eight seconds.
But something on the order of magnitude of that eight-second time: 10, 12, 15 seconds to get that kind of data coming down.
Once you get into the higher speeds that you're talking about, 14 megabits per second, then you're also starting to look at just how quickly all of the equipment involved can handle the data.
Sometimes, your router won't be fast enough (although that's not very common).
Sometimes, the upstream equipment is actually too busy to give you your full 14 megabits per second.
You've indicated that you're getting a pretty good download speed of 14 megabits per second. I'm assuming you're using things like speedtest.net to verify that; but that's really the difference. It's a very common confusion.
Remember that files are measured in the number of bytes they contain;
But your download speed is measure in the number of bits that are
Next from Answercast 37 – My email program won't receive after I dismissed a malicious pop-up. What do I do?
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