You could try the workarounds I already provided in this thread:
I noticed awful freezes during IO operations as well. While I can't tell why this is happening, I can offer a workaround. Here's how:
In a terminal, type
echo "deadline" | sudo tee /sys/block/sda/queue/scheduler
Try moving or copying larger ammounts of files again. You should notice a huge difference. If so, make the change permanent by typing in a terminal:
gksudo gedit /etc/default/grub
In the line beginning with
GRUB_CMDLINE_LINUX_DEFAULT="", add the following string in between the
Save and exit. After that, type in a terminal
FYI: This changes the so-called scheduler to 'deadline'.
Another Possibility would be to lower dirty_ratio settings.
To test it, type in a terminal:
sudo bash -c "echo 10 > /proc/sys/vm/dirty_ratio"
sudo bash -c "echo 5 > /proc/sys/vm/dirty_background_ratio"
If this helps, make it permanent by editing your sysctl.conf:
gksudo gedit /etc/sysctl.conf
At the end of the file, add the following lines:
Save, close and reboot. Done.