Most definitely the xenon CPU as it is a server CPU :-)
A Celeron processor. Some Celeron processors are somewhat powerful, however Atom processors are slower, intended for basic use in ultra-mobile machines such as netbooks.
The Xeon processor is stronger than the Celeron processor.
You can play games on laptops with an Intel celeron processor, but not all games.
There are Celeron dual core processors today. However, just because you have Celeron processor, it does not mean your Celeron processor is a dual core processor. The easiest way to tell is to look at the Intel sticker on your computer. If it says "Dual Core," then it is dual core. If it does NOT say "Dual Core," then it is not dual core.
Intel
AMD
As the Celeron D is a product line and not a specific processor, there is no specific comparable processor. Depending on the model. the Celeron D is comparable in performance to various Athlon 64, Athlon XP, and Sempron processors.
The Xenon processor is a specially designed PowerPC-based processor for the Xbox 360 gaming console.
Yes. Multitasking is dependent on the operating system, not the processor.
celeron
64