As you can see, a lot of today's games are able to make use of the multi-core technology on offer from the i7 920. The question is exactly how many cores do we really need to get the most performance out of our games? Well, to be completely honest three cores seem to be the sweet spot, but this would depend on how much extra it costs for the fourth core to be added.
If dropping a core from a quad core CPU resulted in a 25% price drop, then a tri-core i7 processor could be the goods for most games. If dropping the core only dropped 5% off the price, though, it simply wouldn't be worth it.
While in the past a higher speed dual core would be the better choice for people over a lower clocked quad core, that doesn't hold as much truth these days. Quad core CPUs really overclock extremely well these days and games are able to make use of more than two cores, meaning that you're going to get better performance out of a quad core based CPU.
I really wonder if this was a similar conclusion to what AMD came to when they decided to release tri-core CPUs. It was just unfortunate that their technology wasn't up to the standard that we had become accustomed to, or they could have become a real winner in the value for money department.
Just one more note before I sign off; one thing that I thought would be interesting was power usage. Dropping off cores didn't drop power usage in any way that would make a difference. So if you thought about dropping a core off to save some dollars on your power bill, don't bother.