My base model 15" with the 450 has issues with the keyboard, so I'm returning it for a new one. While the 450 handles the 4k screen rather well, there are still animation lag and stutter here and there. There is a big difference between the Intel 530 iGPU and the 450, so I was thinking even more GPU power could help. I might get a 2nd 4k monitor down the line as well. Would I see a noticeable difference by getting the 460 instead? Thanks!