+yassir560 Your PC has a Skylake processor, therefore it probably has integrated HD 530 graphics.
My rough guess is that a 750 TI discreet GPU is about twice the graphics power of the integrated HD 530 on your CPU in 1080p gaming.
And a GTX 970 is almost precisely three times the processing power of a 750 Ti in 1080p gaming.
The RX 480 (which came out 2 days ago) is approximately equal to a GTX 970; depends on which games you play.
The best value for your money is either of the two cards that I previously recommended to you.