He did that by ajusting his bus speed to a dangerous level.
Your frequency is your multiplier times your bus speed... You're doing it the safe way, which gets you as close to your maximum overclock as you can go.
Notice that he has low-end parts in there? That's intentional, as he was going for a record: he upped his bus speed to the point where he probably fried his USB ports. (And if he put a heavy load on the computer would probably also fry his SATA ports, PCIe slots, and DIMM slots.)
He also had above average cooling as well. I would look at a lot of people's overclock especially not on that site because those tend to be people going for their max clock speed not there everyday speed. I think you might be able to get 4.1 to 4.2 if you push the voltage but idk what the safe voltage is for the cpu.