Depends on the games you play - do you play heavy multiplayer games or games that need more than 4 cores? Games like these include Assassin's Creed Origins, Shadow of the Tomb Raider, Battlefield One and V, and a few others. If you do wish to play these games, then the i5 44400 will indeed be a bottleneck, so I would honestly hold off this GPU upgrade until you have the budget to upgrade to a new PC. If you just want to get the GPU upgrade out of the way right now, then yes, an RTX 2060 would be a decent upgrade from 960, it's quite a lot faster. But with the RTX 2060 and i5 4440, expect heavy CPU bottlenecking in some games, and mild bottlenecking in others.