Computer Parts Explained
I’m going to discuss the basic terminology behind computer parts. If you want to participate in this forum, build a new computer, or just know the power behind video games, this thread will hopefully serve as a useful, but not overly complicated resource. The basic technology of a computer is a bunch of transistors switching on and off, at certain frequencies. This accomplishes quite a lot but to do the tasks we require, a computer needs a lot of different components. This thread will tell you what each one does, and the relationship between them.
The Central Processing Unit (CPU)
The CPU is the brain of the computer. This is what does all the heavy hitting in day to day use, and lots of behind the scenes work in video games. It’s essentially made up of microscopic transistors turning on and off to represent true or false. It also contains a small cache used to store information in direct use by the CPU.
The CPU works by taking input, decoding it into a language it can read, and then acting on the input and producing an output. That is considered one CPU cycle. There are two distinct ways to measure a CPU. One is in Hertz. A hertz is how many times the CPU cycles per-second. The other is millions of instructions per second (MIPS) which is how many millions of instructions the CPU can act upon per second. The two numbers often relate but not always. For instance, a CPU may have a lower frequency, but get more done per cycle; hence it could have a low frequency yet still a high MIPS. The higher both numbers, however, the better.
Some CPUs are multi-core. Multi-core processors are generally just multiple CPUs in one unit and one socket. They improve performance while multi-tasking, but don’t stack when applied to a single task. For instance, a 2 core 3ghz processor doesn’t work like 6ghz, but rather allows you to use two programs at 3ghz speeds.
CPUs are connected to the motherboard via socket. Each type of CPU has a different socket type. Make sure that your CPU will fit your motherboard by comparing their socket.
The Random Access Memory (RAM)
RAM is where the computer keeps information it needs to readily access available. For instance, when you’re running a game and loading it, while it’s loading the game takes all the information off of the hard drive and places it onto the RAM, because the RAM is much faster.
Now you might wonder, why don’t we just replace hard drives with RAM? There are two reasons why we don’t do that. The first reason is due to size and price. Creating a RAM chip the size of a hard drive would be, if not completely impossible, incredibly expensive. The second reason is because RAM is volatile. Due to its nature, when it loses power it forgets all the information on it. This is because all the data on it is electrical, not physical.
RAM can be measured in several statistics. First off is the size of the RAM. This won’t affect performance, but it will affect crashes. If you run out of RAM, your computer can and probably will crash. Having extra space usually isn’t a bad thing. At the time of this article, a good amount of memory for day to day tasks is 8 gigabytes, but that’s likely to change in the future as it becomes cheaper and developers start utilizing more of it. The second way to measure RAM is in its operating frequency, or hertz again. This is the rate at which the RAM works. So when you load up a game, when you go to load a level the CPU will make a call for some information on the RAM. The speed of the RAM affects its rate of sorting through information and finding the correct data. The higher that this number is, the better. Finally RAM can be measured by latency. This is the speed at which the RAM gives the CPU the information. The lower this number is, the better. Consider it like ping in an online game.
It’s also worth pointing out that there are different types of RAM. There is DDR, DDR2, and currently DDR3, though that number will continue to go up. There isn’t any huge fundamental difference with each type, though the pin numbers and speeds generally improve. When buying RAM, make sure you check which DDR type you need.
Finally, there’s ECC and non-ECC RAM. ECC RAM is mainly used by people that need good debugging. (For example, website servers often use ECC RAM.) If you’re building a desktop computer, you probably won’t need or want ECC RAM, but when buying RAM make sure you check that it’s compatible with your motherboard.
The Graphics Processing Unit (GPU/Video Card)
Now that we know what a CPU is, and RAM is, it’s time to explain the GPU. The GPU is a highly specialized and entirely separate processor, similar to a CPU except it’s more geared towards floating point operations used in rendering graphics.
It’s made up of multiple components, and each component can be measured in different ways. It has on board a processor capable of fast rendering of 3d objects, and this usually has to do with massive amounts of specialized cores, numbering in the hundreds, in each processor. High end GPUs are typically more powerful and run much hotter than CPUs, but are incredibly specialized. They can be measured in hertz, and as a general rule of thumb, they have a slower clock speed than a CPU. GPUs also have a certain amount of VRAM. VRAM is dedicated RAM on the GPU used mainly for rendering purposes, such as storing vertex data and texture files. It’s also much faster than normal RAM, and is measured in the same specifications. The only difference with VRAM is that it’s called GDDR. So GDDR3, GDDR5, etc.
Some GPUs are integrated, such as laptop ones. They generally share RAM with the CPU, and otherwise operate similarly, but are much weaker.
Each GPU connects in an expansion slot, unless it is integrated. When buying a GPU, make sure it fits in the proper expansion slot on your motherboard. (PCI, PCI-E, PCI-E 2.0 x16, etc.)
The Hard Disk Drive (HDD/HD)
The HD is a mechanical drive capable of storing memory for very long amounts of time. It physically traces the information onto a magnetic disk. The concept behind it isn’t dissimilar to a cassette, though there are several differences. (Which are very technical and I’m not going to get into them.) Hard Drives use a mechanical arm to trace vast amounts of information onto the disk, and being one of very few PC components with moving parts, they are one of the most prone to breaking. The hard drive is by far the slowest PC component, though it is by no means slow. The disk typically spins at 7200 rpms, though more energy efficient models spin at 5400 and server drives (where information is constantly and randomly accessed) at 10,000 rpms.
The HDD connects to the motherboard via cables. Make sure that when buying a HDD you check the connections. Some connections are backwards compatible, but not all, so be sure to double check.
The Solid State Drive (SSD)
The SSD is basically a long term storage device with no moving parts. Thus in theory it lasts longer, but is also incredibly faster. SSDs can operate at speeds close to that of RAM, and if you’re looking for a loading time boost, this is the part to check out. As of the time of this article, SSDs are very expensive and if you’re looking for bulk storage, be advised that a HDD is definitely the way to go. Many people combine SSDs and HDDs, having their operating system on the SSD for faster boot times, and long term storage on the HDD.
It generally connects to a motherboard the same way as a mechanical HDD.
The Motherboard (mobo)
The motherboard is difficult to describe in technical terms. In essence it contains a number of different parts that connect all the other parts previously described together, and creates the computer. There are many different controllers on the motherboard, and always a chipset. I’m not going to go into detail about them, but be sure to research them extensively before buying a motherboard, as certain chipsets might not let you do certain things like overclocking.
Motherboards only accept certain types of each component. A motherboard might only accept DDR3 RAM, Socket 1155 processors, and might not have a PCI slot on it, and only a PCI-E, etc. Be sure to make sure all your components are compatible with your motherboard. You also want to make sure it will fit into your case, so be sure to check the size specifications. (ATX, Micro-ATX, Mini-ITX, etc.)
The Power Supply Unit (PSU)
This is the single most important part of your computer. This is the unit that supplies power to all your parts. Its job is straightforward, but if you get a cheap one it could cause serious damage to your components. Always ask around about quality as that’s an ever changing issue, before buying one. Make sure that it supplies enough wattage on the 12 volt rail for your graphics card, and enough wattage on the other rails for the rest of your computer.
Also make sure that your power supply will have the correct types of connectors for what you need. Check that against the individual parts' requirements. Finally, make sure that the power supply will fit into your case by checking it's size standards. (ATX, Micro-ATX, Mini-ITX, etc.)
The Chassis (Case)
The Chassis is pretty simple. It is the physical case that you store your computer's parts in. When selecting one, I currently advise to select an ATX form factor one, as most parts are made for ATX size specifications. This ensures that you will have more parts available. It's also recommended that you choose one that's durable and has good airflow, as both of those can quickly become issues.
If you have any additional questions on how certain parts function, or what their function is, feel free to ask here.