On last night's episode of Conan, Iron Man 2 and 3 co-star Don "Rhodey" Cheadle complained about the weight of his Iron Patriot suit compared to Robert Downey Jr's light and comfortable Iron Man armour. Is this power armour racism? Of course not.
The difference in weight can easily be explained. Tony Stark's armour is powered by the arc reactor embedded in his chest. Cheadle Man's armour requires an external power source, hence the extra-added weight.
"But Fahey, in real-life neither of them have an arc reactor in their chests." Let me stop you right there.
*leaves the room, doesn't come back*