my friend has a duel core desktop and when he played it on ultra settings, gameplay was very smooth, with very little lag, and graphics looked amazing

his specs were:

Athlon x2 64 2.2 ghz dual core
2gb ram ddr2
nvidia 9800 gt

he gets around 20-30ish fps outdoors and 60 fps indoors

can someone explain how he is able to play on ultra with those specs? especially a duel core processor?

Ultra specs in Skyrim isn't any thing extraordinary it has the same level of graphics that Oblivion and Fallout 3 has which I played using a lesser CPU 1.8 core 2 duo and a 9600 (even with mod enhancers for Oblivion)

Skyrim only utilizes 2 cores even if you have a quad core processor.