I am planning on buying new pc & i am wondering (couldnt find info on this anywhere else)
is there a motherboard/s that support 2 or more cpu chips on them?
Two Core i7 920 chips on 1 motherboard
Two Phenom II x4 955 on 1 motherboard
Please dont ask we what do i need it for "because each of em has already 4 cores"
Not only do you need to buy a motherboard that has two CPU sockets (obviously), but you also need to buy CPUs which can work with multiple chips in the system. For example, the Core i7 chips cannot be used with more than one chip per system, but the Xeon X55x0 series (very similar to Core i7) can have two chips per system.
A while ago there was the Intel Skulltrail (an Intel board which could support two high end processors) which was cool and all but was limited by FB-DIMMs which were very expensive, weren't widely available and in some cases were hard to "tune" (in regards to timings).
Multisocket boards are typically designed for servers, and then, such boards tend to have an awful integrated graphics processor with no graphics slot, preventing their use as a desktop. Though, you may have a look, now that Pci-E is "often" capable of both - disk raid host and graphics card. But be careful, most chipsets can do both, but Bios not necessarily...
On the other hand, you get a lot more processing power from the Gpu than from any number of Cpu sockets. Some applications begin to take advantage of it, especially since DirectX10 hardware and Cuda libraries.
So maybe you could find such appropriate software? Then it runs on a graphics card (either nVidia or Ati, generally not both) or on a special GPGPU card, which contains one or more Gpu and no video output, like Tesla. Ati has similar offers, though they're late.