is stock cooler enogh for i7 4970 non k?

Yes, the stock cooler will be just fine since you have a non-overclockable (well you can overclock it a little but meh) CPU and heat output of the CPU will not be enough to justify investing in a aftermarket CPU heatsink / cooler.
 
1. I think you mean i7-4790, not 4970.
2. The stock intel cooler will do the job.
Two reasons to change it out:
a. It is a bit tricky to install.
b. Under load, the 92mm fan can get noisy.

I might suggest a simple tower type cooler with a 120mm fan. About $30.
cm hyper212 for example.
 


YES, without question the stock cooler is just fine for gaming and all your needs. Intel would not include the cooler if it did not meet the needs of the cpu under normal conditions.