Mac Pro freezes in sleep mode

I am on a Mac Pro (Late 2013) running OS X El Capitan Ver 10.11.1

This is a slight difference in language because my computer does not freeze when I try and wake it; it freezes while it is asleep so I cannot wake it.

My issue is that I am working on my computer and will walk away for an extended period on time. Many times I come back and the screen saver is swirling away and I am can go right back to work after waking the system with a tap of my Wacom pen to the tablet. Other times, however, I come back to find the screen saver is frozen in mid-swirl and the air quickly venting from the top of the harddrive is exceeding hot. The only way to resolve the problem is to do a hard restart of the computer. After the restart, the fan will slow down and the vented air will be much cooler.

This was an issue with the previous OS and continues to be an issue with El Capitan.