I see why your temps are so low. Your core voltage is only set to 1.3v. I seriously doubt it's stable at that voltage. Just because you're not seeing errors does not mean the system is stable.
Run Realbench on the stress test for 8 hours.
Run Prime95 version 26.6 (No other versions) on the Blend test for 8 hours.
If it passes both of those at that voltage, with no worker stoppages, then you have the greatest 6700k that ever came off the production line.
You will want to keep HWinfo open the entire time so you can visually see if a worker gets dropped. Otherwise, it will continue testing using the other workers and you may not even know it. When a worker stops or errors out, HWinfo will show zero or very low usage of that core and it will not resume work during the remainder of the test.