FPS has it's up's and down's - 0.5s freezes

[Cerativ]

Hello

I have changed my graphic card recenlty. Got 1070 instead of 780.
Did not have this problem before
I encounter FPS problem everytime I try to play any game. FPS is just not stable. It jumps form 80 FPS to 40 and then back on 80 FPS -frustating - over and over again----------------- I would call it small freezes which last like 0.5s and then fps go back to normal
You guys might say "it's prolly the problem with new graphic (broken or so)"
but I checked it, it's alright. I have reinstalled windows, does not help

I'm using
processor : i5 2500k @ 4.2 GHz - it's OCed well, that's not the problem
mobo : asrock z67 extreme3 gen 3
ram : 8gb kingston's
power suply : xfx 550
gpu : 1070 GTX
win 7 64
The tempreture's and alright too. Does not go over 73 celcius
I experience something like this, maybe a little less - https://openload.co/f/cW0u8DEHHMk/witcher3_2016-10-08_15-42-07-80_x264.mp4#

Any ideas?

 

[OCD Tweaker]

73c you gpu temp?

did you increase you volatage when you OC you CPU?

 

[Cerativ]

I mean, 73 on cpu, gpu max is 60~ In stress of course

 

[OCD Tweaker]

i looked up some 1070's and they require a psu higher than 500 watts you have 550 watt PSU and your OC your CPU

im assuming your fps drops while fighting or when the game picks up

have you tried running your CPU at stock CLOCK?

 

[Cerativ]

Where did you read about that. Just one comupter component needs 500 W PSU? Is that a joke right? Ubelieveable
The fps jump even when I am just running straight f.e. in witcher. It's not like - heavy stress and then fps gets low- It is like from time to time, you get me?
but but, to disprove your thesis I will check it, I have another PSu - OCZ modxstream 600 W

@edit
I have just read, that 550 W is higher than enough for that card, cpu and OC summed. There's even some spare power left
I also restored my CPU to default and still the same. THat's not the OC

Solution has to be somewhere else