The 3400G (a 2nd gen CPU wtih integrated graphics) is going to be limited in it's minimum FPS, so will likely not be thriving in minimum frame rates not matter what GPU it is given, so I'd probably be looking to see if your current mainboard is R5-3600 or even R3-3300X compatible before upgrading my GPU, as the 1660 is fairly competent at 1080P....