Is it possible to use a dual processor computer as your desktop?

Dual processor desktop. Is it possible? Yes.
Should you do it? -- don't bother unless you have custom requirements for it.

In fact, do not even go beyond Dual Core processors.
Do i7 and Nehalam architecture in general have advantages? yes.
Recheck your need for a multiprocessor setup and take the call.

There are a lot of other hardware parts you can use the money on.
Memory for instance: Dynamic, Magnetic or Solid State these days!

In normal desktop applications, the bottleneck is almost always I/O. So I'd say spend your money on one of those new Intel SSDs and lots of fast RAM.

It depends on the operating system you want to use. If you want to use Windows XP Home, I'd say it does not come with a multi processor kernel.

But the question is: Why would someone use a multi processor PC as a desktop PC? What about dual and quad core CPUs?

There is no reason why you could not... but beware that typically this might mean you need a whole bunch of components specifically suited to the motherboard too... from specific processors, to ECC memory, to in some cases, special expansion cards.

There is however a potential benefit in that multi-socket motherboards typically have a much better aggregate memory bandwidth than a multi-core-single-socket solution with the same total number of cores. Not to mention that there are usually more memory sockets meaning you can put a whole lot more memory in, which may make sense depending on what you intend to do.

It's possible and great, but expensive solution. And if you didn't use software, which can use multi-processor, then it's useless.

If you are developer or you using VM software, you get some improvement. But still this question is subjective. Each user have opinion for this.

Developer

• 1st CPU
  • OS, IDE, clients and others
• 2nd CPU
  • VMs with servers (same configuration like production server)

But if you want better performace for your OS, it's better invest to SSD HDDs (Intel or Samsung), because HDDs is most slowest component in computers.

Multi-core vs. Multi-Processor Performance

Multi-core Vs. Multiprocessor, the advantage? at The Joel on Software Discussion Group