Trisquel is slow on dropdown lists and wireshark

I noticed this problem with Ubuntu but never occured me with Trisquel until now (at least I only noticed it now).

In the most past of dropdown lists and with Wireshark capture running, Trisquel is quite slow.

How to reproduce (dropdown) :
1 - Open empathy contact list
2 - Click on the "+" button to add a new account
3 - Click on the dropdown list with the available accounts for login
4 - Move the mouse up and down and see the lag.

What should happen ? --> It should move without lag like on any non-debian based distribution.

What happens ? --> It is slow to move the mouse on the list making a simple task take longer than excepted.

How to reproduce (wireshark):
1 - Open Wireshark
2 - Select the network interface
3 - Press "Start"
4 - Open a browser and start browsing the net (or just open a video on Youtube).

What Should happen ? --> Wireshark shouldn't freeze when only 500 packages are captured. My Fedora/Arch Linux based instalation can handle up to 500 000 packages until they begin to hang, and it stops to hang if I stop the process of capture of the packages.

What happens ? --> Wireshark freezes every few seconds for a period of at least 10 seconds, making it painfull (and impossible) to use in Trisquel.