gyuho945 :
It's only $20 difference and I can't seem to find difference between them.
Only difference I see is 14 + 3 phase, 8 + 2 phase.
What does the power phase do? How does it affect?
Which one should I choose?
The 14+3 is going to be a better card if you are doing extreme overclocking. Basically, it delivers a more stable voltage to the GPU which results in more stable overclocks. Running mild overclocks, you probably won't notice a difference. But, if you have the money for a 980ti, you might as well spend the extra $20 and get the better card even if you are not OC'ing.