How to build the fastest PC - Well the most important question to ask yourself when starting out in the task of building the fastest pc is,
What do I want to use it for?
The answer to this question will affect some of the decisions and costs involved. The components making up a PC are as follows:
The choice of motherboard, CPU and RAM have to match and there are deals to be made on core bundles where these components are matched and all you have to do is connect them together.
Motherboards have a specific socket for the CPU and these must match. Motherboards also have memory (RAM) slots that also have to match.
Power Supplies have a certain type of power connection to the motherboard and so choosing the correct PSU for the motherboard is also important.
Choosing a Case is based on the form factor of the motherboard (ATX, Mini ATX etc).
If you are doing a lot of gaming, or if the software that you use requires a high resoluion or is video intensive then you will be best to use a seperate graphics card rather than rely on the onboard VGA socket on the motherboard. If you require multiple monitors then you need either a dual output card or even 2x cards.
Most motherboards will come with an onboard Network NIC connector. This may be limited to 10/100 MBs and if you wanted a Gigabit connection then upgrading to a Gigabit netwotk PCI card is something to consider.
Desktop Motherboards wont come with WIFI - if you need this to connect to your internal network then you need either a PCI card or USB device.