imac 2017 performance

hello everyone.. My friend has bought new imac 4k 21.5 inc retina 2017. He needs it for rendering video by Adobe After Effect, and he was try it up. but, he got a problem.. his imac not working as expected. It works slower than in rendering, it works like in windows before.. my friend told me...

Hello, I bought a new 2017 i7 4.2 ghz 8gb ram ,512 ssd, radeon pro 580Imac. My question is i might be wrong but im suspicious about its performance, i didn't run some tests. The reason im suspicious is as u know according to your configuration os x puts u at some level of scaling at that 5...