D/L speeds in Windows

[Omatic810]

I've always wondered why download speeds start off as fast, and slowly slow down as time goes on. Is there a term or reason for this? BTW, I'm talking about D/L off of a site or FTP.

[kanezfan]

it's only because it takes you a couple seconds to click save as, then open the location where you want to save the file. So let's say you download at 300kb/s, it takes you like 2 seconds to pick where the file is going to be saved. While you're picking where to save the file, it's already started downloading in a temp location. Then the browser sees you have say, 700k of the file already, so once you click ok, then it thinks you can download at 700k per seconds. That's basically it, although I'm sure someone else can give you a better technical answer.

[Gobbles]

To shorten Kanez answer...

its buffered downloaded information. Kinda like when you do streaming media.

[Omatic810]

Oh, that makes sense. I'd always yell at my PC "Why are you slowing down!? WTF!? etc etc.". That "estimated time remaining" thing is very inaccurate in that case, you gotta wait a minute to get past the buffer.

Anyway, the universe is at peace again. Thanks!

[entropy]

I'm not so sure. What about BIG downloads? Like you said, it only takes a few seconds to choose your location, so only a bit is buffered. What if you're downloading like an ISO? The speeds still decrease pretty consistantly... :confused:

[Shivian]

Well for the most part it is averaging but it also can be a function of the tcp/ip protocol. Correct me if I'm wrong someone (and I'm sure someone will!) but tcp/ip works via a method of "additive increase/multiplicative decrease". So the speed of the transfer will increase at a linear rate until an error occurs. Then it will suddenly jump back (eg by 50% - hence the multiplicative decrease).

My observations seem to indicate that due to the nature of the aforementioned, speed starts pretty quickly but throw a few errors in and your speed takes a very significant hit. Then your download speed that your browser or download manager reports is obviously going to start going down as averaging slowly sets in and will settle to a value below the lofty heights that it started.