Problem when download files with download managers?

[darkflames]

My current problem is, a couple download managers that I have used now have done this, the first one was the WoW download manager when it downloads patches, it will work for maybe a minute or so download fast then my internet just goes really slow and the speed drops. The second one was today when im trying to download americas army. It starts downloading at ~100 then goes up to ~400 then eventually goes from 700kb to 900kb after a few minutes my internet just goes really really slow and the speed drops to 60kb a second. Now if i download a file without a download manager usually the files download around 900kb-1.2mb per second and the internet speed seems the same as usuall.

Does anyone know why it is doing this?

My internet speed is about 11mb download and 760kb upload if that helps anyone.
Im using vista ultimate x64, and my computer is hard wired to the router.

 

[Arch]

What kind of router? Blizzard's download is peer-to-peer based, which can easily swamp / kill a cheap home grade router. I'm not sure about America's Army though.

 

[darkflames]

well it did it on my belking F5D7230-4 router but i have a new router now the Linksys WRT54G2 and thats what americas army is doing it on