Hey everyone, I have taken the liberty of writing up this FAQ for anyone interested in building or purchasing a desktop or laptop PC.
Let's start off with the basic components:
Motherboards - The motherboard is the main housing unit of all your PC components, and it is required that all your parts match your mobo's plugs. There are many different types of motherboards that can handle different types of CPU's. Depending on which CPU brand and model you choose, your mobo's socket type must match your CPU socket type.
Leading manufacturer(s): Asus
CPU (Central Processing Unit) - Your CPU is the heart of your PC's power, but not always does your CPU clock speed (measured in Gigahertz per second) depend on how fast your computer will run. Your CPU also requires other components like your RAM. CPU speed can also be dependent on bus speed, cache and bit rate. The recommended bus speed for a CPU is 1600mhz and the usual cache size is 1MB, although 2 is recommended. There are different processor types, 32 bit, 64 bit and dual core processing. For optimal gaming performance right now, 64 bit single core processing is really recommended, although in the coming months dual core processing will start to become utilized in gaming and general software fields.
Main developers : AMD and Intel
RAM (Random Access Memory)
RAM is a very important component in your PC, as the more RAM you have, the more programs you can run at one time as well as higher end software and games. Laptops and desktops both use different types of RAM, as well as certain motherboards can utilize dual channel memory. Laptops use SODIMM memory, while desktops use various types of DDR memory as well as SDRAM (although SDRAM has a very slow clock speed). Video gaming consoles use a different type of RAM as well, all 3 console developers use their own unique types of memory. Recommended memory size is at least 512MB, although 1GB is best if you want Windows to run almost flawlessly, 2GB and 4GB are also available for supported motherboards.
Leading developers: Corsair, Kingston, PNY, Ultra and US Modular
GPU (Graphics Processing Unit) - Many motherboards come with integrated Graphics processing units, however most are very low end setups, such as ATI's Radeon 9200 graphics chip which is a very mainstream unit. Laptops come with shared GPU, half of the memory from the GPU is shared with the CPU for optimal efficiency, which is generally a problem for mainstream laptop computers and those who want to play games on them. However buying a independent GPU is the way to go if you want optimal performance, and depending on how much you like pretty graphics, your GPU setup will be different. For the optimal graphics technology, a SLI (Nvidia GPU based) or Crossfire (ATI GPU based), which allows for up to two GPU's to run at one time, also allowing for users to use 2 monitors at the same time and maintain high quailty graphics depending on the card. Nvidia has recently unvield its GeForce 7950GTX which is two video cards in one single card along with a motherboard which can run two of those GPU's at one time in Quad SLI mode. GPU's require different slots depending on the age of the card. AGP was the standard for a long time, which originally took over the PCI card, however now PCI Express is the mainstream slot for graphics card.
Leading developers: ATI and Nvidia. Other noteable: Intel (laptops and some Mac PC's)
PSU (Power Supply Unit) - The power supply is a very important component in your PC, the more watts you have the better gaming experience you can have, running SLI and Crossfire motherboards and GPU setups require a 500 watt PSU, although generic PC's use 300 watts. It is recommended that anyone planning on using Quad SLI mode should purchase a PSU of at least 600 watts. ATX is the connection from your PSU to your motherboard. A PC case usually comes with a PSU.
More will come later.
Just noticed this and it's rather old.
The leading manufacturer are way off on a lot of places and you've gotten som basic stuff wrong as usual.
Clock frequanzy is measured in Hertz (Hz) NOT heartz per second. One hertz is one clock cycle per second. Hz/s would be cycle per time squared which is some kind of acceleration or change in speed. It's also worth noting that frequenzy can only be used to compare processors with the same architecture. A 2 GHz P4 dual will not as fast as a 2GHz Core 2 dual. Both have two cores and and both have 2 GHz but due to the better architecture the Core 2 will win. Also a dual core processor is recommended for gaming right now but soon the quad core or more will take over.
2 GB RAM is enough for most users with XP. If you are using heavy applications 4 GB is recommended. Due to the extreme low cost of DDR2 you might as well get 4 GB at once. Vista needs more RAM.
Worth noting here is that most XP users will only be able to see about 3.5 GB of RAM because the regular XP version is 32-bit. This means it only has the ability to handle 2^32 addresses which equals to 4 GB. Some of those adresses are needed for other stuff than RAM though so mainly depending on what you have in your computer you will only be able to use ~3.5 GB of your 4 GB. This is also true for the 32-bit versions of Vista and any other 32-bit OS out there. To use more RAM (which currently only servers have a use for) you need a 64-bit OS that can handle 2^64 addresses which is several millions TB. Yes that's billions of GB.
PCi-E is still standard for GPU and now motherboards with both SLI and CrossFire capabilities are becoming more common. You don't need to graphics cards to use two monitors though. Most modern Graphics cards has two DVI ports.
Chassis with built in power supplies are becoming rare now and due to high powered graphics cards you need bigger and bigger powersuplies. An average GPU now peaks at 100W and the high end cards with multiple GPUs on the same card can need up to 300W for the card alone. A standard computer with something like a Radeon HD4850 or nVidia 8800 will need 200-250W while working hard. remembering that even the best powersuplies only has an efficiency of 80% and that they last longer when working at lower loads a 450W power supply is recommended if you are planing to build a gaming computer. Most people seem to buy a power supply that's to big though. There are 1000W power supplies out there and they are only needed when using multiple high end graphic cards such as the Radeon 4870X2 and the nVidia GTX280.
ATX is a form factor and not a power connector. It's the most widely used form factor and it makes sure that all components fit together. There's a smaller versios called microATX.
Not complete in any way but a bit more up to date.