FarCry 3 has some strange things going on with it's system requirements. They are ridiculously AMD biased, so much so in fact that it is hard to take them seriously.
what do you mean by "ridiculously AMD biased"? it does looks odd seeing the 5770 being put in the same recommendation as the 480 and the FX4150 alongside the 2600K.
Minimum Specs
CPU: Intel Core2 Duo E6700/AMD Athlon64 X2 6000+ or equivalent dual-core
Video: Nvidia GTX8800/AMD Radeon HD2900 or equivalent 512MB DirectX 9c card
Memory: 4GB
Recommended Specs
CPU: Intel Core i3-530/AMD Phenom II X2 565 or equivalent quad-core
Video: Nvidia GTX480/AMD Radeon HD5770 or equivalent 1024MB DirectX 11 card
Memory: 4GB
Hi-Performance Specs
Video: Nvidia GTX680/AMD Radeon HD7970 or equivalent shiny new DirectX 11 card
CPU: Intel Core i7-2600K/AMD Bulldozer FX4150 or equivalent quad-core
Memory: 8GB