KoHinoor Singh :
i read somewhere that gtx 1060 = gtx 980 so why we cant play modern games at ultra settings and also gtx 1060 supports 4k gaming
The 1060 sits somewhere between the 970 and 980 performance wise, and I can tell you holding 100+FPS on some of the latest titles on ultra settings 1080p is not feasible on that class of card. Play something like Witcher 3, the newest Assassin's Creed games or Rise of the Tomb Raider on ultra and you're going to struggle to hold 60FPS constant, let alone get 100 or more. The 1060 technically does support 4K, but it's not really fast enough to game at that resolution unless you're only playing old or graphically undemanding games, or you're okay with running low-medium settings at around 30FPS.
If you're willing to turn some settings down in exchange for higher framerates, or you play graphically undemanding games, then getting a 144Hz display might be worthwhile to you, particularly if you play online multiplayer FPS or something else that is fast paced. If not, you can always get a 60Hz display to save some money, or maybe look putting the extra money towards a 60Hz IPS panel instead and get better colour reproduction than what you'd get on a budget 144Hz display.