Driveclub, unlike Forza, isn’t a open world game. That means that Driveclub can render much less stuff at the same time than Forza. While on DC the game only renders the race you select, on FH3, The Crew and NFS the game has to render all the surroundings around you, because you can go anywhere you wany

Does anybody still remember NFS5: Porsche Unleashed? Most of what I know about Porsches comes from that game.