How does speed test work?

[Gauzl]

I live in Australia and in my region I am restricted to ADSL1 which allows me to download at no more then 450kb/s and I dont know of the upload speed, however when I do a speed test it says 3.75mb/s download and 0.79mb/s upload, yet clearly these results don't even compare with my own network, can someone please explain to me how this is suppost to work?

[mvitkun]

I live in Australia and in my region I am restricted to ADSL1 which allows me to download at no more then 450kb/s and I dont know of the upload speed, however when I do a speed test it says 3.75mb/s download and 0.79mb/s upload, yet clearly these results don't even compare with my own network, can someone please explain to me how this is suppost to work?

It works by downloading a small file temporarily and seeing how long it takes to download, by that it estimates your connection speed.

Then based on that it gives you a file that shouldn't take longer than ~10 seconds to download.

You then download that file and it gives a more definite connection speed.

https://support.speedtest.net/entries/20862782-How-does-the-test-itself-work-How-is-the-result-calculated-

 

Also the max speed for ADSL1 is 8Mb/s unless i'm mistaken. 

http://go.telstra.com.au/helpandsupport/-/difference-between-adsl-and-adsl2-

[dalekphalm]

I live in Australia and in my region I am restricted to ADSL1 which allows me to download at no more then 450kb/s and I dont know of the upload speed, however when I do a speed test it says 3.75mb/s download and 0.79mb/s upload, yet clearly these results don't even compare with my own network, can someone please explain to me how this is suppost to work?

Okay, so to answer your question, we're going to have to learn a little math, and a little bit about how computers and more specifically data works.

 

Computer Data is at it's core, a binary math system. The basic component of computer data is the Bit

A Bit (Shown as lower case 'b' is either a 0 or a 1 (on or off, yes or no, true or false, etc). A Byte is (shown as upper case 'B') is made up of 8 bits.

 

Now, because the system is base 2, instead of base 10, when you reach the next size of unit, it works like this:

1024 Bits = 1 Kilobit (shown as "Kb")

1024 Bytes = 1 Kilobyte (shown as "KB")

 

Often people will not bother to show the appropriate lower or upper case, out of ignorance or laziness. This can cause confusion and misunderstanding.

 

So now let's look at your stats:

Download speeds of no more than 450 KB/second (Kilobytes)

Speed test showing 3.75Mb/second (Megabit)

 

So now for the math:

 

First, take the speed test result, 3.75 Megabits, and convert that into kilobits. To do this, we take the number in megabits and multiply by 1024 (1 Gb = 1024 Mb, 1 Mb = 1024 Kb, 1 Kb = 1024 b, etc)

3.75 x 1024 = 3840 Kilobits

 

Now we take that result, 3840 Kilobits, and convert it into Kilobytes, which is a more useful unit of measurement, since this is what you see when downloading files from the web. Now, remember that there are 8 bits in a byte, so we must divide the previous result by 8.

3840 / 8 = 480 Kilobytes.

 

Therefore, according to the speedtest, your download speed is equal to 480 Kilobytes per second.

 

Now speedtest servers are generally very high speed servers with lots of available bandwidth, and low latency. Therefore this represents the ideal theoretical speed limit. The actual day-to-day speed will generally be slower, as you noted when you said your downloads max out at 450 KB/s.

 

Hope this helped!

[WaruSaru]

Edit: seems like some one beat me to it

I don't really know what's the max download speed for adsl1.

But I want to make sure of something.

When you said 450kb/s did you mean kilo-bit (Kb) or kilo-byte (KB)?

If you meant KB then it's ok, speed test is in bits not bytes.

Now since there is 8 bits in one byte a 3.75Mb/s is actually:

3.75*1024= 3840Kb/s

3840/8=480KB/s

Someone correct me if I'm wrong here.