I'm experiencing a weird problem with my Kubuntu installation. I'm running 14.4 now that was upgraded at least twice using the built-in distribution upgrade. The problems started after the last upgrade to 14.04:
Copying files from one place to the other, often different drives, is very slow and often freezes.
Network transfer to and from other computers is dismal at sub 2 MB/s. That goes for both Samba and FTP. The Internet works fine and I'm getting my full download speeds of 400 KB/s.
In most cases the file manager and dialog boxes freeze with blank content when I open them, sometimes for a few seconds some times for a few minutes. Sometimes the folder tree pane in the file manager freezes but the file/icon pane works. This didn't happen much in the last 48 hours which is coincident with a kernel upgrade (3.13.0-35-generic). A related issue is Gwenview, it opens images fine but freezes for a while when closing it.
I benchmarked my network connection and speed from another computer using "iperf" and it rated my connection at 91 MB/s so I'm guessing it's not a hardware or driver related issue.
This problem is with all users on the computer. Everything else on the system runs fine like launching apps and so on.
Any help is greatly appreciated.