So this image describing my problem. When my AVAST in working (even if i will completly turn it off) i have jumps, when i starting windows in safe mode (so avast doesn't start) i have no jumps and this is screen made just right after i deleted AVAST. I have jumps only while GPU is on idle, ingame it's ok (but if i will mininize game and core clock will go downm jumps will start again). And one more thing - when i turing my PC there is no jumps. But right after i play game, even 30 sec jumps will continue untill i will reset my PC.