Ubuntu not recognizing all CPU cores

I'm not new to Linux but I'm not an expert either, so bear with me if this is a stupid question.

We're running Ubuntu 14.04.2 from a live session USB to test out a new dual CPU workstation. It has two Intel Xeon E5-2650V3 processors, which are ten-cores with hyperthreading, so I should be seeing 40 CPU's in System monitor. For some reason I am only seeing 32 CPU cores. Is there a limit to how many Ubuntu can recognize?

I'd only be seeing 20 CPU's if one of the processors wasn't installed correctly, so I doubt this is a hardware problem. Under "About this computer" I am seeing "Intel Xeon(tm) E5-2650 V3 Processor (2.3 GHz) x 16"

Here is the output of lscpu:

Solution 1:

This have been reported as bug in Ubuntu 13.10 :

https://bugs.launchpad.net/ubuntu/+source/libgtop2/+bug/1210280

It affected only 2 people, therefore the fix never maked it into production version. I am suspicious that it was never fixed afterwards, so it is still in 14.04.2.

I think, you can dowload the fix for yourself and compile your own version of libgtop2 if you mind.