I'm on Windows 7 64-bit, and have tried WS_FTP, FileZilla and SmartFTP to upload files. With all three clients, transfer speeds are almost zero. They start at around 3-4kB/s, then drop fast to 0.2 and the like. Seriously! It's ridiculous, and I've been trying for 5 days now to figure it out.

This happens with more than one server, as I am transferring files for various web design projects.

What could be causing this to happen?