Decreasing Download/Upload transfer speed

Recently reformated my computer and reinstalled smartftp. I have same settings for firewall and my router.

But i have a problem with transfers

For example if i am downloading a file, the transfer will start at 140kb/s and decrease down to 2kb/s within like 10 mins. It never did that before the reformat.

Same thing with uploads. Starts at 40kb/s but slows down to 2kb/s

there are no limits to transfer speeds in the settings. i already checked that.

Any Solution?


Thanks for the help.