Hello everything is supported. I did a heavy upgrade on my imac.
I7 860s - 2 SSD (leave super drive) - 32gb ram - new gpu nvidia quadro k1100m
but the computer is quite powerful, but not much.
there is a bottleneck as the video card is very powerful and the cpu can't handle it.
I think I'll switch to an 880 i7 processor or a xeon 3480. my only dilemma is whether my imac power supply will be able to handle the watts of the new one.