It's not something you need a degree for, not something that requires extensive training. But it is so easy to get lost in the flood of information out there. Think of this article as an executive level summary. It'll save you time and bother if you don't have the head for spending weeks searching every web crevice for advice.
[This article went long, so I have divided it into two. The three-part series just became four!]
Every desktop computer is made up of a few basic parts: a case, a power supply, a motherboard, a processor chip (CPU), memory (RAM) and a hard drive. Most will also have a separate graphics card, though sometimes you can get away with using whatever graphics chip the motherboard provides. With today's fast CPUs you need a dedicated CPU cooler so it doesn't melt the first time you go to use it. Stuck inside the case and sometimes on the CPU and graphics card are fans to get air flowing; you might supplement these or replace them with quieter or more efficient models. Finally you will likely need access to other forms of storage media. Once upon a time people used floppy disks. Today you will need a DVD burner and maybe a memory card reader.
Everything else you think you might need (USB ports, Internet access, networking, audio) is on the motherboard. Of course if you are building an audio workstation you'll want a better audio interface than the default, but if all you're doing is listening to MP3 files and movies you are good to go. You will need a keyboard, mouse and computer monitor to allow basic I/O needs. But for the purposes of this article I'll restrict myself to the computer proper and forget peripherals.
OK, that's it. I count nine components. Let's take them one by one, making top-level decisions and noting the prices one can expect. Important decision points will be in boldface.
Motherboard and ProcessorI'm going to start with the motherboard since that is the core of the system. You can choose either a full-size ATX or a smaller Micro-ATX board. In cases where you want a series workhorse with a lot of connectivity, choose ATX. If you need to make a system as small and inconspicuous as possible, say for a home theatre computer or streaming media server, choose Micro-ATX.
Motherboards support different chip sets and those chip sets support different CPUs, made by different manufacturers. To simplify this decision tree, our first choice will be between Intel and AMD CPUs. Years ago Intel was the only game in town (Motorola for the Mac) but AMD has long since produced fast competitive chips. The problem is, I remember applications failing based on a non-Intel processor being installed. Maybe that doesn't happen any more, and maybe it only happens in highly specialised cases, but I prefer to have one less thing to worry about.
A more practical concern is that AMD tend to get more computational bang for the buck by running faster and therefore hotter. This translates into paying less but having a noisier system. That makes sense for some application, but not the one under discussion.
So, to play it safe, Intel it is. To get top performance at a reasonable price there are currently two choices in CPU lines, the Core i5 and the Core i7. Both have multiple cores, which means they are like several chips in one. (Actually it's more complicated than that... way more complicated.) But all we need to know is that they are speed demons, faster than the Core 2 Duo chips that preceded them. Though it does help to be sure your software can take advantage of the multiple cores, every application benefits when multitasking, because then the operating system itself can allocate tasks to different cores.
Unfortunately there is yet more terminology: The Lynnfield line of these chips plug into the socket LGA 1156 and the Bloomfield line plug into socket LGA 1366. Let me tell you why this might matter.
Core i5 is available only in Lynnfield and has no upgrade path. Core i7 is available in three different sockets and will grow in the future. But does this really matter? I say not. No-one ever bothers upgrading just the processor in an older computer. When the time comes you get a whole new motherboard plus processor -- that way you get the newest features across the board (no pun intended).
The current choice is simplified by the performance-to-price ratios of the Core i7 chips, some of which simply don't make sense. The decision boils down to the excellent performance of a socket LGA 1156 motherboard with a Core i5 chip or the even fastter socket LGA 1366 paired with a Core i7.
CPU prices start at £140 and go all the way up to £800 for the most excessive i7. I'll target £200; though this is somewhere near the bottom it will allow for most of the performance benefits of this line. Motherboards start at £80 and also go on up into the stratosphere. I've seen some at over £400 but will try to keep the price at £150.
CPU CoolerThis was the least familiar part of the process for me, because last time I bought a computer we didn't have CPU coolers, just a little fan to push some air. Now every sort of device under the sun can apparently be put to this task, ranging in price from £8 to £70 and up. Some come with a fan and some don't. Some can support up to four fans. Others are designed to help cool other parts of the motherboard in addition to the CPU. The only way I can choose between all of these is to try to aim at the lower price range and pick one that will fit inside my case. So let's target £30.
CaseMini Tower or SFF (Small Form Factor) cases are ruled out by our choice of the motherboard. These days Desktop cases are infrequently used. Why would we want a computer taking up desk space? And besides, that brings the noisy components closer to us. This leaves us with the rather vaguely-defined Tower cases. You'll find terms like Full Tower, Mid Tower and Midi Tower (nothing to do with MIDI of course!) in use. These are just convenient (though obscure) labels for how big the darned thing is and how many drives you can fit in it.
If you are a gamer, a crucial factor is how much room there is for over-sized graphics cards. We don't care about that but must be sure there is enough room for our choice of CPU cooler. It's not always easy to find this important datum.
Prices are in the range of £40 to £300 or more. Some might come with a power supply, but we will consider this item separately. I'll aim for £100 for the case.
Power SupplyThese come in a standard size for ATX cases, though there are some odd-ball form factors out there. One should never compromise on a power supply, since having a clean and consistent source of current makes the rest of the computer sing a happy tune. However, it is also very easy to pay over the odds for a super-powerful PSU that you don't really need. These are designed for either server systems with many components or gaming rigs with multiple graphics cards. One-upmanship has steadily increased the base power people think they need (whether they do or not is another story) from 300W to over a kilowatt.
That said, it is often best to get a PSU beyond your required needs, so that it can work at a fraction of capacity. That often improves efficiency and is a good trick for keeping the noise down.
Typical prices are in the range of £40 to £200. I'll try to stay below £100.
RAMThe more memory, the faster every piece of software runs, especially when multiple apps are open at once. However, the maximum RAM the operating system can utilise has a limit point. For 32-bit operating systems this was effectively 3GB, which is why I'll be running a 64-bit OS. Whether you go that route or not, 3GB might be enough for your needs. But if you are using sampler software, intensive graphics or video programmes and so on, then the more the merrier.
Current motherboards use DDR3 RAM that comes in sticks of 1GB or 2GB. Boards for Core i5 are dual-channel, meaning you must add two sticks at a time. They might have 2 slots, 4 slots, or more, but always some multiple of two. Boards for Core i7 are triple-channel and have 3 or 6 slots. Using 2GB sticks, this equates to a memory capacity of 6 or 12GB respectively.
RAM runs £20 to £30 per GB for the best possible brands. I see no reason to compromise there.
Graphics CardWelcome to a world of hurt. There is nothing more head-wrecking than trying to figure out the insanely complicated lines of graphics cards on the market today. The two main manufacturers, ATI and NVIDIA, have a dazzling array of products that even seasoned reviewers cannot figure out. NVIDIA will bring out a new card with a higher model number but lower performance. Company X will clone an ATI card but re-clock the chip or change the memory or the cooling system or something else to make it different. One card is good at benchmark X; another card is better at benchmark Y. Manufacturers put cheats into their firmware to perform better at the artificial benchmarks but less well in real-world tasks. And so it goes.
We are not building a gaming rig or a system for CAD, and so can forget about the bleeding edge. On the other hand there's no point in getting something low-end and finding out that all the games one wants to play won't work. And it's not just a matter of games. For smooth video playback, better colour rendering and faster general screen redraw times, a better video card will result in a smoother computing experience. If you commonly score film this is particularly important, since you need to see the video playback alongside a complex application interface and waveform patterns, all tracking in real-time.
Perhaps the simplest way of classifying graphics requirements is in terms of the Microsoft DirectX system. Today DirectX 11 is the latest and greatest. Before that there was DirectX 10.1 and previously DirectX 10. That's where we will pitch our tent. It's a couple of generations back but you will still be able to have luscious renderings at decent frame rates (depending of course on the card specifics).
We require the card to support multiple video outputs. I'm happy with two and that is quite commonplace. If I need more down the line I can put in a second cheap card.
The final requirement is the one that narrows the field the most. Though some cards with active cooling (that is, fans) can be quiet, I will restrict myself to passively cooled cards that I know will be silent. This might require careful tuning of case fans to prevent things from getting too hot. But remember that most of the time the graphics card will be doing very little; it is only in bursts that the GPU (graphics chip) tends to heat up (unless gaming).
Cards range from a little over £20 to £2000. Yes, really, that number has three zeroes. How about we stay under £100?
Hard DriveHard drives just get bigger and bigger, and just as well with all the media files, sample banks and what-not we need to store on them. These days 1.5 TB models are perfectly good performers in terms of energy consumption and speed. We'll need at least two of those plus a smaller drive for the operating system. In my case I already have 3TB of storage and so will budget for just a single drive and move some of the units from my older computers.
There are two other storage options to consider. If you do lots of client work it is handy to have a dedicated hard drive for each client that you can swap in and out of your computer. This requires a drive caddy and these are still expensive.
Second, instead of using a hard drive for your OS disk, you can accelerate performance by going for a Solid State Drive (SSD) solution. The cheapest models have poor controllers and are not always a lot faster than a HD. The better ones are still dear. A 1.5 TB HD can be obtained for £75. A 64GB SSD is twice that. Hmmm...
DVD BurnerThese are now commodities that go for peanuts. But some are a lot noisier than others and it is not always easy to tell which models will be quiet. because though the engineers might have had this as a priority, the marketing boffins don't tend to let us know the truth with any clarity.
If you want to play Blue-Ray video then budget a lot more for the player and be sure your graphics card and monitor can decode the HD content.
ConclusionI hope this has been a gentle introduction to the components your computer needs. In the next article in the series I will cycle through each of the nine components again and make specific recommendations. I will also give you links to resource sites I've found particularly handy. Then you can go spelunking for details if you wish.