Really, this is the CPU to buy if you're going to get in on the Sandy Bridge-E action and to be completely honest, we knew that before we had even tested it. We knew that before we had even gotten a sample of it. The "X" / "Extreme Edition" processors from Intel have never represented value, instead they're represented the best performance possible.
The model below that, though, represents performance that's only slightly slower, and value. Combined with good overclocking thanks to the "K" nature of the 3930K, it's the processor to buy if you're going to go down the path of X79.
It might even be the CPU worth considering if you're looking at going down the Z68 / 2700k path. Sure, it will mean a move over to the X79 platform, but the extra $230 US associated with the $599 US 3930K isn't that much, especially if you're interested in significantly improved performance outside your games and in CPU intensive tasks.
The 3960X is a tough buy, and we said that originally. The price associated with it makes it look extremely scary and when you consider the extra VGA power you could throw into that system with the $500 US saved on the CPU, you're going to end up with a much faster system.
If you demand the higher cache on the 3960X, sure, get that. If you're also buying four HD 6970s or four GTX 580s with the CPU; again, get the 3960X. If you're only looking at getting one HD 6970 with the 3960X, or one GTX 580 and you're going to be doing a lot of gaming, step back for a second and think about the extra video card you could throw into the mix if you moved to the 3930K instead. Two GTX 580s on a 3930K are of course going to offer superior gaming performance to a single GTX 580 on a 3960X and both setups are near identical in costs.
The 3960X will continue to be the CPU that everyone wants, and for good reason. It's got a bucketload of Cache and offers the highest performance of any processor out of the box. The 3930K will be the CPU that everyone actually buys, though, and all for good reason.
If you're set on the 3960X, outside of maxing out every component in your new system via 64GB of RAM, RAID 0 SSDs and three or four Video Cards, you need to just sit back for a second and see what you could do with the money if you picked up the 3930K over the 3960X.
The 3960X and 3930K are both absolutely fantastic processors and if money doesn't matter, buying the 3960X is an easy choice. Want similar performance, though, and really want to save some serious money? The 3930K is an easy choice.
In the end you've got two fantastic processors from Intel which accompany the new X79 motherboards perfectly. Outside of a 100MHz down clock out of the box and 3MB less cache, the only major difference between them is one will leave an extra $500 US in your bank account.