The others beat me to it. Things are a little mixed up. That is easy to do.
I just happen to have an Intel Core i7 860 system which is based on Intel's LGA 1156 cpu socket. The 860 systems use DDR3 dual channel memory. The Intel Core i7 920 is based on Intel's LGA 1336 cpu socket and uses DDR3 triple channel memory. The dual channel and triple channel memory modules are not interchangeable.
The Intel Core i7 860 was designed for mainstream professional applications such as video processing, graphics design, and scientific work. That's where the 860 has a slight edge. If you are an avid gamer, then I suggest you consider an Intel Core i7 920 system. The 920 is better suited for gaming.