We get a lot of questions about building computers here, so I figure a general guide might be helpful. I'll stick to general home-use computers since that's what I'm familiar with - someone else can talk about server builds if desired. (I will probably throw some home theater PC stuff in since it's not dissimilar, just generally lower power.)
Building your own machine is not a difficult process (and has become much easier over time from what I understand), but picking parts can seem overwhelming your first time around. There's a lot to think about and making sure things will work together is the difference between a working computer and a pile of parts. So why do it? Well, there's a few reasons: for anything but the absolute cheapest machines, you can pretty easily put together a desktop computer that will be cheaper than anything you can buy prebuilt, and you can be assured of the quality of the parts. It will also leave you with something built exactly for your needs that is likely to be more upgradeable and customizable in the future. The one major negative is that instead of having a single company to call when something goes wrong, you're stuck diagnosing problems yourself and dealing with several companies based on the diagnosis. (For this reason, I would never build a computer for someone, but that's just me.)
THE BASICS
There's the parts you'll need:
CPU: This is the brain of your computer. It controls everything. Without it, you have nothing. There's two major vendors at the moment: Intel and AMD. There's a nice thread here for more information on them. In general, Intel will cost more, but will also perform better than AMD, but there's obviously going to be some direct competition, and AMD certainly shouldn't be counted out for budget builds. Every CPU has a socket design it will fit into, which should be clearly noted on whatever place you purchase it from. Price will vary by what you're doing, but $200-250 for a mid-range part is not to be unexpected, though you can certainly go much cheaper here.
Motherboard: If the CPU is the brain, the motherboard is the torso. Almost everything else you put in your machine will connect to this, be it directly into it or with a cable. This can be a bit more difficult to pick, but start with your CPU. As noted above, the CPU will have a socket design, so look for motherboards with that socket. From there, search for the features you want: number of SATA ports, number of USB ports and headers, expansion slots, SLI/Crossfire, audio, etc. Pretty much every modern motherboard will have built-in audio and ethernet and some have wifi. For a standard desktop, you probably want a full ATX board - they'll fit in any full sized case and will have plenty of expansion ports to keep you happy. For HTPC builts, a mATX board will likely suffice, but they can be used for larger machines just as well, though there's not really much reason to do so unless you're limited on space. Some generally respected brands include Intel, Gigabyte, Asus, MSI, EVGA, and Asrock. I tend to budget around $150 for a good one.
RAM/Memory: Memory is what the CPU reads directly from. Conveniently, it's also fairly cheap. At this point, both Intel and AMD are using DDR3, so that makes picking parts easy. For a gaming machine, I would recommend a minimum of 8 GB, but 16 GB isn't a huge increase in cost, but any more is at best unnecessary and at worst unusable (Windows 7 Home Premium is limited to 16 GB, though higher versions do not have this limit) at the fastest speed you can afford. Personally, I tend to get a major brand's low-end line since I don't normally overclock, but that's entirely up to you. Some of those brands include Kingston, Corsair, Crucial, Patriot, and G.SKILL.
Storage: This is where all your files and programs and such live. There's currently two types of storage available: hard disk drives and solid state drives. HDDs have been around awhile and are, by far, the better value for your money when it comes to space. SSDs, however, are quickly coming down in price and are significantly faster as well as being completely silent and lower power than a hard drive. I'm personally of the opinion that a smallish SSD plus one or more large hard drives is the best use of your money, but that's just me; others will say a large SSD is better and others will claim SSDs are still too expensive (and they likely are for a budget build). A 128 GB SSD will hold a complete OS, pretty much every program you regularly use, plus a few games with space to spare. It's not uncommon to find this capacity under $100 now. I won't claim to be an expert on SSDs, but I've heard to avoid OCZ as their failure rate is notably higher than their competitors. I've been using Corsair with good luck, and Intel and Samsung's SSDs are also supposed to be quite good. As far as hard drives go, brands seem to be as contentious as religion (and, objectively, every manufacturer has had both good and bad models, so it's worth doing some research on a specific model), so I won't make any specific recommendations, just to avoid "green" drives for anything more than backup. They're designed for low power rather than performance, so they spin down as much as possible and are typically lower speed. Other than that, look for 7200 RPM or greater drives to fit your budget and I would recommend a retail box as they come with MUCH longer warranties than equivalent OEM (unboxed) parts (get the longest warranty you can, though most people will note that if it doesn't fail in the first month, it'll probably outlast the useful life of the rest of the build). In either case, make sure it's a SATA interface not IDE (or even SCSI), since motherboards are not really shipping with anything else for the most part. Expect to spend around $100 for a 1 TB HDD.
Graphics card: This is technically optional now with both AMD and Intel including integrated GPUs on their CPUs, but if you're playing games, you want a graphics card (HTPCs can exclude - pretty much any integrated GPU currently being produced can decode 1080p video without a hitch). There's two companies making GPUs -AMD and Nvidia - who then sell to a bunch of card vendors who make the actual cards. I'll admit I don't really keep up with GPUs too much since I only buy one every two or three years, but both companies have pretty similar lines and tend to go back and forth on the best value/performance at any given time. It's better just to ask either this thread or a separate build thread for specific recommendations. We could probably create a whole thread just explaining graphics cards. One thing to note is that both AMD and Nvidia have systems to allow multiple cards be used in a computer. In most cases, it doesn't make a lot of sense unless you're planning on spending a lot of money. You'll need a motherboard that allows it and a big enough power supply to run them all. Some good card manufacturers are pretty much the same list as motherboards. Anything modern should only be available with a PCI-E interface, so there shouldn't be any confusion here. Prices will depend entirely on what you're doing, but $200-250 is generally the price/performance sweet spot.
Power supply: The PSU is the one part to absolutely not cheap out on. A failing PSU can kill your entire computer dead. The good news is that even a good PSU is not going to break your budget, since power needs are regularly overestimated. Pretty much any single-GPU system should be well served by a 550W PSU, maybe even less! I tend to go by what GPU manufacturer recommends as a minimum and stick with that, but this site is a very handy calculator. You'll find that actual power usage will probably well below even 550W. PSUs also come in modular systems where the individual cables can be removed if unneeded. It's handy for cable management, but not necessary and does drive up cost. Some good brands of PSU are Antec, PC Power & Cooling, and Corsair. $100-150 should get you something quite good.
Case: While not technically necessary, it's far preferable to having a bunch of parts sitting on your desk. I'm not going to get into this much, just look for one that's at least as big as your motherboard (an ATX motherboard will need an ATX or server ATX case, while mATX can use those or an mATX case) with the features you want: external USB and headphone jacks. I prefer simple, unadorned cases, but others like windows and lights and the case market is big enough to accommodate everyone, so just find whatever you like, it'll probably be fine. The only thing I can suggest here is that a removable motherboard tray can make things easier to put together. I'll also note that there's toolless cases that have pretty much all parts attached without any screws or anything, but I find them less secure than traditional cases. You can spend as little as $50 (or less, probably) or as much as several hundred on this. If it comes with a PSU, you probably want to throw it out unless it's one of the manufacturers above.
Operating system: You need something for your computer to run, right? For most gamers, this will be Windows 7, but I know there's some Linux gamers out there and Windows 8 is out in October. OEM Windows 7 Home Premium discs run around $100 and retail versions are $180. (Most likely you do not need Professional or Ultimate, but if you find you do, MS offers an "anytime upgrade" for some money that you can upgrade to a higher version.) The major difference is that OEM copies are technically tied to the hardware they're initially registered to, but MS isn't too stringent on this and will usually let you transfer the license if you build a new machine. Make sure you get a 64-bit copy since there's no 32-bit CPUs being made anymore to my knowledge. Linux is free, but I don't use it and therefore can't talk much about it.
OPTIONAL
Here's some parts that might not be strictly necessary or you might already have:
Heatsink fan: This keeps your CPU within its operating temperature - too hot, and it dies. Most or all retail CPUs will come with one that will be pretty much the bare minimum for that CPU. This is perfectly fine, but if you want something quieter or intend to overclock or are getting an OEM CPU, you'll want an aftermarket heatsink. There's a large number available, but read reviews and make sure it will work with your CPU - they typically will have a list of sockets they work with and come with the necessary hardware for the motherboard.
Optical drive: This is to play and burn CDs, DVDs, and Blu-Rays. It's not strictly necessary, but physical media is still very common and you might want to rip a CD or DVD or something. It also means you don't need another computer to put together a bootable USB drive to put your OS install on. A basic DVD-RW is around $20 and Blu-Ray player/DVD-RW is closer to $60. Pretty much anything will do here, but like HDDs and SSDs, make sure it's SATA and not IDE.
Case fans: Your case might come with some. It might not. You might want more. You might want quieter. Just make sure your case has the necessary spots to put them and read reviews from there. Bigger fans are quieter than smaller fans for a given airflow. These can run anywhere from a buck to double digits. Look for ball bearings rather than sleeve bearings as they tend to last longer.
Card reader: You might have some SD or CompactFlash or even Mini Memory Stick Duo EX Plus Alpha cards sitting around you want to connect to your computer. No need to use an external USB port for a reader when you can put one in your computer and maybe even get an extra USB port or two! Find one with the cards you want (it's hard to find ones without any specific cards, really) and read the reviews. This'll run $20 or so and fit into a 3.5" external slot (or a 5.25" with an adapter - 3.5" are becoming less common in cases as floppy drives become less common).
Floppy drive: It reads and writes floppy disks. You probably don't need one. I don't think my current motherboard even has the header for one. In any case, if you need one, get one, I guess.
Wifi card: If you want to connect to a wifi network, you'll probably need one of these, but some motherboards have it built in. (I haven't seen a modern motherboard without ethernet, so that shouldn't be an issue.) On Windows, pretty much any card will come with the necessary drivers and work well enough. Look for 802.11n cards, potentially dual-band so you can hop on the much less crowded 5 GHz band if you have the necessary equipment.
Keyboard: Not actually optional, but you might have one already! Don't cheap out here, though, since it's one of three parts you directly use your computer with, so why not get something nice? What's nice? That comes to personal preference, so I'm not recommending anything. I will note that wireless can be nice and reduce some wiring, but isn't necessary.
Mouse: See keyboard.
Monitor: Like the mouse and keyboard, not technically optional, but you might have. Similarly, it's what you look at, so get something nice to look at. In general, I much prefer an IPS LCD panel over a TN LCD panel, though TN can have something of an advantage in pixel switching speed, but I game on IPS without a problem, so I think it's an overstated advantage. IPS panels generally cost a bit more, but put side by side, I can't go back.
Speakers: I don't really know enough about these to talk about them. Gaming is better in headphones, anyway!
Audio card: This processes audio in your system. Most or all modern motherboards come with at least integrated 5.1 sound if not 7.1, but there's some legitimate reasons for a discrete audio card. If you have those reasons, you probably already know this way better than me and don't need me to explain.
Cables: Pretty much all retail parts come with the necessary cables and connectors (and then some) to get them hooked up, but OEM ones usually do not. You'll have to look into the specific parts to make sure you have everything you need.
Tools: Depending on your case and everything, you may need a screwdriver or two (Philips and flathead) and a hex driver. That's pretty much the most of it, though. A grounding band is a good precaution, as well, but not strictly necessary if you otherwise follow good grounding practices.
There's lots of other parts and accessories you might want or need, but I'm not going to go into them since they start to run into really specific needs that aren't worth addressing.
Statistics: Posted by Endless Mike — Tue Aug 07, 2012 4:19 pm UTC