FTP Transfer Fails After 20mb When Downloading From Site

I am having a problem transferring files from my website to my PC. I am using Windows 8 Professional, and SmartFTP 6.0.2110.0. After starting the download it will transfer anywhere from 20mb to 40mb and then the transfer speed drops to zero, and no more of the file is transferred. If I let it sit, it eventually goes into the retry sequence and never restarts. This happens on any large file. Smaller files, less than 20mb, transfer ok.
If I go to cPanel and download the file, it downloads normally until finished. I recently upgraded to the latest version of SmartFTP, but the problem existed prior to that.
Windows is up to date.
Thank you for any assistance you may provide.
Bob Weiner