Leo De Harsh,
"Intel i7 3960x or 3970x ?" > These two processors are very similar, and to me deem to be the same except that the Intel i7 3960x has a 3.3GHz base clock speed and uses and 130 Watts and the 3970x has a 3.5GHz speed and uses 150W. The prices are almost exactly the same and both may be overclocked to stable speeds of 4.2- 4.4GHz with some people claiming 4.6GHz stable. As the speed can be the same overclocked, I'd steer towards the 3960X which uses less power and is therefore running a bit cooler.
"Is this Possible to use Dual Intel i7 3960x or 3970?" > In short -no. It is not possible to use i7's in a dual CPU configuration, for that you have to use Xeon processors with model numbers beginning with "2". Xeons are configured for a certain calculation emphasis, have more cache, typically run at slightly lower clock speeds, consume less power to run cooler, can display 10-bit color, and importantly can use ECC- error correcting RAM. Important benefits of being able to use two CPU's are that it increases the number of CPU cores/ threads, PCIe lanes, and the amount of RAM that can be assessed- I've seen eight Xeon server motherboards that can support 768GB and even 1024GB of RAM- there can be more slots all round! Xeons are also quite a bit more expensive than i7's, the 8-core E5-2687W cost $1,900 and many Xeons are in the $1,200-1,500 range. If you're budget is really "unlimited", there are 10-core Xeons that can be used on 8-CPU boards that cost $4,500 each- giving you 80 cores / 160 threads for about $35,000, and then 1TB of ECC RAM at close to $9,000. then I'd add two Quadro K5000 graphics cards for $3,800 and four Tesla K20X GPU coprocessors for about $32,000, RAID controller and drives another $7,000. With that system you could play several of the most intensive games at highest settings simultaneously and then make a 3D dynamic model of the Asteroid Belt or Pacific Ocean for relaxation.
If you'd like a quick specification for a high performance gaming PC > i7-3960X or i7-3970X overclocked to 4.2GHz , ASUS Rampage motherboard, liquid CPU cooling, 32GB -1866 RAM, 2- NVIDIA GTX 680 video cards, 2- Samsung 840 SSD's in RAID 0 (a system that divides the work of two hard drives to increase performance) for operating system and applications, 2X 2TB, 64MB cache Western Digital or Seagate 6GB/s hard drives in RAID 1 for file storage. RAID 1 creates a "mirror" drive so if one drive fails, the other is an exact duplicate that "rebuild" the replacement drive. When RAID 0 fails, both drives are lost as they each have only 1/2 of the files so you would keep a "system image" on the storage drives that can restore the operating system, applications ans files quickly. Get a high quality dedicated soundcard and amplifier/speaker system with subwoofer. To this system, you would want a 850 to 1200W high quality power supply and do research into the best liquid cooling for the CPU's, the variants of GTX 680's and possibly liquid cooling base plates for those, and a roomy case with plenty of fans that can be speed controlled and good air flow. Look into cases, power supplies, and fans that are rated for quiet running. There are a lot of choices, but such a system might cost $3,200-$4,000.
The process of choosing high performance and compatible parts - not every part works with every other part- should be approached carefully and with a lot of care and understanding of what each component does and at what level each choice performs. Assembling and configuring a system is not extremely difficult but does require a methodical approach that can be demystified by watching YouTube videos- though you have to filter through the piles of bad ones.
That is a kind of generic high performance gaming computer and I imagine others will have more detailed, and specific performance targeted choices.
Cheers,
BambiBoom