How do I know if my overclock is properly done?

deadgamer2

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Feb 11, 2013
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CPU is i5-6600K.

I know there's a thing called "Stability testing". My overclocked CPU passed Intel Burn Test without crashing, getting error messages or BSOD.
My temperatures aren't too hot, maximum it goes is usually 60 degrees Celsius. I have a Cooler Master Hyper 212 EVO cooler.

But I feel like I've done something wrong. The scores sometimes fluctuate. For example:
For Intel Burn Test
Test 1: 97
Test 2: 106
Test 3: 100

For Cinebench R15
Test 1: 627
Test 2: 640
Test 3: 633

When I add a little bit more voltage (like 0.005 or 0.01), there are less fluctuations. Am I doing it correctly, or is there something more?
Here's an example:
Intel Burn Test:
106
106
105
106

Sometimes, while running Intel Burn Test, applications (like MSI Afterburner) disappear for a second, then it reappears.
 

deadgamer2

Honorable
Feb 11, 2013
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10,540


Sorry I think I didn't word it properly.

MSI Afterburner blocks the desktop. It disappears for a second, and comes back.