Uploading slows down download speed (partyl solved)

Problem is: since today my download speed goes down to about 70kb (it should be 600kb) when i upload a file to RS via browser interface. No matter which carrier i choose. If i interrupt the upload the speed rises to the old level.
Anybody has the same experiences?
I just updated my firefox to 3.5, i hope that's not the problem. I always had the same slowdown when uploading to RS using the RS-Uploader (old and new version), but never had the problem in the browser.

maybe the Rapid-Uploader uses the maximum speed to upload the files in order to less the uploading time

ibtesam wrote:
Thanks, ibtesam, but how does this affect the download speed. Even if i set a maximum upload speed in RS-Uploader, download speed goes down to the same level. In former times when i uploaed via browser the upload speed was a little bit slower when i started a download and that was ok. But now i can hardly surf the web, it's horrible slow. I remember having the same trouble when uploading via a ftp-uploading tool.
Well, this seems to be a pretty unique problem, cause i found no help in the web. Maybe it's a hardware problem with (old) DSL-Modem and (old) Netgear-router in connection with (old) Win2k system.

[edit] i managed to downgrade to Firefox 3.0.11 and everthing is fine again as it should be