Well paxx, that link while comparing the Xbox to a Gamecube also explains how it works.
The fact is, the Xbox is like a pc and different from a pc.
Here are some qoutes from a different source
For example, there does not exist an XGPU-level graphics processor available for PC combined with unified memory architecture (UMA) and a stripped down Windows 2000 kernel optimized for a game console. PlayStation 2 and GameCube are even more different from a PC design.
Unlike a traditional PC, Xbox uses a unified memory architecture where all processors access the same 64 Mbytes of DDR memory. A 128-bit, 6.4-Gbyte/s bus connects the DDR memory bank to the XGPU, where memory-access traffic is managed. Additionally, an AMD HyperTransport bus connects the XGPU and MCPX, and a 64-bit, 1-Gbyte/s bus links the Pentium III CPU and Nvidia XGPU.
More conventional PC-like touches include a single, daisychained flat-ribbon cable to connect the hard-disk and DVD-ROM drives to the motherboard. A separate internal power supply assembly provides power to the board via a 12-wire cable assembly.
Nearly 1,300 components populate the Xbox, exclusive of the DVD assembly, hard drive and controllers-pretty fancy pieces of design by themselves. Spread across seven separate circuit-board assemblies are 29 ICs and 1,248 discretes, passives and connectors. Yet the total semiconductor die area is 5.3 cm2-less than some cell phones and PDAs.
So, when it comes down to it, these consoles are built like a pc and then differ from a pc optmized for gaming.
I, like many other people, prefer sittin down on a big screen playing on a console pc like or not, with surround sound and the comfort of your couch/chair.
I'm not sure by your last post if you were considering buying a console.
There is also the fact that with consoles, they become outdated because of the rapid technology with pcs, with new graphic cards, etc., coming out every 6 months or so however like I said these consoles are optimized for gaming.
And also like I said before, because of the similarities between the Xbox and a pc, games are easier to develop for the Xbox. Pc developers are already familiar with the architecture and can therefore use this advantage and make better games.