Building Your Own PC, Part 1 Know-How for Do-It-Yourselfers – THG.RU

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Know-How for Do-It-Yourselfers” –>

Building a PC System

Anyone needing a new computer faces a tough choice: you can either go for a complete system, or you can build your own PC. As most complete systems are cheaper than the sum of their parts, when is it really worth it to build your own?

Under the hood of a midrange PC

Imagine you want to build a new PC and want to use a few remnants from your old system. If you were satisfied with the performance of your CD-ROM drive, hard drive, printer or monitor, then it could be worth it to simply buy the remaining components – you might not even need a new case.

We also hope that this article will reach the individualists among you, i.e., users who know exactly which processor, motherboard and graphics card they want to install, but who just don’t know how to fit it all together. The third group of users we want to reach are those people who only want to swap out a component, whether a graphics card or a CPU.

Many are intimidated by hardware. Some people won’t even put in a new card on their own if they can help it. Yet the computer is now a mass-market product that, thankfully, has also brought about broad standardization.

This article will guide you unerringly through each step of successfully building your own PC. Of course, this article assumes that you know how to properly handle electronic components, that you know how to use tools, and, perhaps most importantly, that you take pleasure in this kind of tinkering. As we are going to introduce a large spectrum of PC components, users who only want to upgrade individual parts can skip certain sections in this guide.

Standard Components Of A PC System

In our enthusiasm and eagerness to offer a complete do-it-yourself guide, we picked up the price list at the computer store on the corner, only to feel overwhelmed by the sheer quantity of parts on offer. If you aren’t yet used to buying a PC in individual components, it can’t do any harm to draw up a list of everything you need before doing anything else. That said, a complete PC system requires the following items:

PC case

Motherboard

Processor

CPU cooler

RAM

Hard Drive

Standard Components Of A PC System, Continued

Graphics card

CD-ROM or DVD drive

Floppy disk drive, if needed

The following items shouldn’t be forgotten:

• Monitor
• Keyboard
• Mouse

These components are necessary to run the new computer, including its operating system (e.g., Windows, Linux).

Extra Options For Special Applications

Depending on what you’ll be using your PC for, you might need the following components as well; please note, though, that this list is by no means complete:

Case and Power Supply

Power supply

The advent of processors breaking the gigahertz barrier has made one thing clear: their thirst for power is hard to rein in. When buying a case, take a very close look at the built-in power supply. In addition to the classic ATX power supply, it should also feature an auxiliary power connector. More and more motherboards require this plug to cover the power needs of a Pentium 4 or an Athlon XP. The only time you won’t need it is if you’re operating a CPU at 1400 MHz or less.

Classic ATX power supply plug.

Extra current for power-hungry CPUs: ATX12 (left) and P6 connector. (right)

An increasingly familiar sight on motherboards: on the left, the P6 (AUX); and on the right, the classic ATX plug.

An ATX12 socket on the motherboard.

Power Connectors For Drives

Your power supply will depend on how many drives you plan to install. Small cases only offer three or four connectors. Once you’ve used up all the available connectors, you’ll have to use a Y junction to turn one plug into two.

One into two: a typical Y junction with large plugs.

This cable also comes with small plugs for connecting floppy drives and the like to a power supply.

Cases: More Questions For The Salesman

Always make a point of asking about assembly materials: are all the screws, spacers and other accessories included with the case? A small bag of assembly materials is usually stuck to the inside of the case. Always be wary of cheap offers!

A bag of screws should be inside the empty PC case.

Always make sure you have spacers and mounts to secure the motherboard. A few screws for the case won’t hurt either, as they are generally also used to anchor plug-in boards. The screws for mounting drives (hard drive, CD-ROM, etc.) have a finer thread. You need at least four for each drive, but it’s always a good idea to have a handful of replacements. By the way, you’re barking up the wrong tree if you start looking for these screws at the hardware store. Go to your local computer store – they won’t have to look far for the screws you need, and they’re bound to be the right size. If possible, avoid plugging the monitor directly into the PC power supply – you’re better off with a separate connector. While some power supplies offer an additional plug for a monitor, you’d be well-advised not to use it for screens larger than 19 inches – the high surge at power-up is a frequent source of booting problems.

Ask about the form factor. This depends on the motherboard. Since almost all new motherboards conform to the ATX form factor, your case will have to be ATX compatible. You can still scrounge up AT cases for AT motherboards. A modern ATX motherboard can be identified by the fact that all the jacks for the keyboard, mouse, parallel printer, and serial COM port are soldered directly onto the motherboard. We’ll document this in the section on the motherboard.

This and That: Screws, Spacers & Jumpers

Typical case screws are used to screw on the case covers and anchor plug-in cards to the case.

A drive screw’s thread is finer and thinner than screws used for the case. The head is smaller, too. This kind of screw is generally used to affix the drives in the drive bays, and to screw the motherboard to the case.

Spacers are screwed into the backplate for the motherboard.

What Are Jumpers?

Jumpers are short and sweet.

A jumper is nothing more than a metal bridge that connects two contacts. We don’t see the metal, though, because it’s covered with plastic. Jumpers are often used to configure the PC. For instance, you can use them to set the processor speed or change a drive from a “master” to a “slave.” Pictured above is a classic jumper, as used on drives and boards just about everywhere.

Motherboard Overview

Main components of a motherboard.

The image shows an ASUS motherboard. At the top on the right-hand side are the interfaces and connectors that stick out of the case at the back of an assembled computer. This board is designed for AMD Athlon and Duron processors. Socket A, as it’s called, is labeled “CPU socket” in the picture. The expansion slots are to its left. The AGP slot is used exclusively for the graphics card. The PCI slots will hold network cards, ISDN, sound or video-editing boards. At the bottom left are the panel connectors for the on/ off button, the hard drive LED, the reset switch, and the operating LED. Take time to familiarize yourself with where they’re located. By the way, LEDs that don’t light up can generally be fixed by simply turning the plug around. The two IDE connectors (40-pin) are below in the middle, while the connector for the floppy drive (34-pin FDD connector) is in the left side of the image. We’ll describe the cables and drive configurations on the next page.

Onboard Components

ATX connector panel

Keyboard, mouse, two serial connectors, a parallel port and two USB ports are on the ATX port panel. Some motherboards, like the one here, feature optional sound and joystick jacks. There are also models that have a monitor connection. That saves a slot and some money, but you’ll have to deactivate the onboard chip if you plan to replace these cheap onboard modules with a higher-quality expansion card. It’s generally impossible to run both chips at the same time. Once again, it can either be done in BIOS or with a jumper. Check your handbook to find out which method to use.

Basic Motherboard Configuration

Many modern motherboards with integrated software configuration no longer require you to do anything prior to assembly. That means that you type your processor parameters directly in BIOS (Basic Input Output System). Most of the time, you access the BIOS menu by pressing the DEL key, F2 or F10, shortly after switching on the PC. Check your handbook to find out which key to use. The latest technology even recognizes the CPU automatically, a feature that is particularly useful for beginners. But making settings manually is still a must for anyone who wants to fine-tune his or her system.

Processor Settings: FSB and Multiplier

The external clock speed is usually referred to as the Front Side Bus (FSB), or system clock. Typical physical frequencies for system clocks are 100.00 and 133.33MHz. The actual processor clock is calculated by multiplying the system clock with the multiplier. For example, a Front Side Bus of 133.33MHz and multiplier of 13 results in a physical CPU clock speed of 1733MHz. Some manufacturers provide “marketing” figures when Double Data Rate (DDR) or quad pumping raises effective bandwidth. Here’s an example of such marketing figures, which have been placed in quotes:

AMD also lists a so-called P-Rating, or Number Modeling, for marketing purposes. In other words, an AMD Athlon XP 2100+ actually only runs at a physical speed of 1733MHz. “2100+” is merely a way of comparing the processor to an equivalent Intel Pentium 4. Put plainly, an AMD Athlon XP 2100+ is about as fast as a Pentium 4 2100.

Setting The Clock Speed

There is no automatic software configuration on older boards. That’s why it can’t hurt to know the three principles of manual configuration. By the same token, overclockers will be more likely to make settings by hand. Here are the different ways to set clock speed:

Obsolete: using jumpers, the frequency table is right next to the jumper block.

Multiplier table for older models.

Occasionally found: setting by DIP switch.

Modern: convenient configuration in BIOS.

Determining which of the three methods applies to you will depend on your motherboard. While the general tendency seems to favor BIOS, you’ll still come across a DIP switch block now and again. The jumper method, on the other hand, is entirely obsolete.

Intel and AMD officially abolished the variable multiplier for their processors some time ago. They wanted to prevent people from overclocking, say, 1300MHz models to 1500MHz. That kind of overclocking would boost performance significantly without costing a dime. For the tinkerers among us, all that’s left for us when trying to eke more performance out of a processor is a gentle increase of the FSB. All the same, there are a few tricks for removing the fixed multiplier, at least for AMD processors. More information on this can be found in the article, Plastic Surgery: Releasing The Athlon XP To Hit 2000+. As the motherboard manufacturers are aware of this, they attract more buyers by offering what is, in fact, a superfluous multiplier. The BIOS screenshot shows this clearly.

Connecting The Floppy Drives

Floppy drives are in danger of extinction because floppies generally don’t hold much data. Most software is generally installed from CD-ROMs now, anyway. CD burners are very popular for archiving data. Nevertheless, a floppy drive can still pay off if you work with old programs or data from time to time.

Floppy connector (34-pin) above, IDE connector(40-pin) for hard drives and CD-ROM below.

It’s easy to spot floppy cables. They usually have a “twist” of individual wires, as you can see in the upper corner of the image. The image shows a color marking on a cable. This is frequently a red line that marks pin 1. Pin 1 is also printed on the motherboard. On modern motherboards, notches and/ or a missing pin in the middle (see picture blow) prevent the cable from being inserted the wrong way. You still need to watch out when hooking up older drives or motherboards. The red dotted line at the other end of the cable should always point in the direction of the power supply. Here, too, there is a reverse-connection protection to keep it from being improperly configured.

Connecting Hard Drives and CD-ROM/DVD

The vast majority of hard drives and CD/DVD drives are based on the IDE (Integrated Device Electronics) standard. There’s also the SCSI standard, which is mostly used for servers or workstations. In comparison to SCSI, IDE is extremely cheap to produce, which accounts for its higher popularity. There are four subgroups within the IDE class: UltraDMA/33; UltraDMA/66; UltraDMA/100; and UltraDMA/133. The number at the end describes its bandwidth. As a rule of thumb, the higher, the better. 133, for example, stands for the maximum data transfer rate of 133 megabytes per second. DMA is short for Direct Memory Access. A beginner doesn’t necessarily have to know how DMA works in order to obtain good results.

Two drives can be run on each IDE connector block. Mainboards usually have two IDE connectors (Primary and Secondary IDE), so that a maximum of four devices can be connected. Modern motherboards with an additional controller can even offer four IDE connectors. If you want to connect an IDE to a drive, it is configured as a “Master” (Single). If, on the other hand, two drives need to be connected, one must be labeled “Master,” and the other “Slave.” The jumpers are used to connect the contacts, thus configuring the drive. The connection to the motherboard is made by way of a 40-pin ribbon cable. It has three plugs – one for the motherboard, and the other two for the two drives.

Most PC systems have one hard drive and one CD-ROM/DVD drive. CD-ROM burners are also a type of CD-ROM drive. The following configuration is recommended for IDE drives:

• Primary IDE: hard drive as Master (Single) Primary IDE:
• Secondary IDE: CD/DVD drive as Master (Single)

Users who want the full allotment of IDE components should connect the drives as follows:

• Primary IDE: hard drive 1 as Master (Dual)
• Primary IDE: hard drive 2 as Slave (Dual)
• Secondary IDE: CD/DVD drive 1 as Master (Dual)
• Secondary IDE: CD/DVD drive 2 as Slave (Dual)

There’s usually a sticker on top of the drive explaining the necessary jumper settings. Or, you can also find a description in the hard drive manual.

IDE jumper table for a Maxtor hard drive.

Port panel on the hard drive: power supply, jumper blocks, IDE ribbon cable (from left to right).

Connecting the CD and/ or DVD drives is basically the same as with hard drives. The same rules apply.

CD-ROM port panel: digital audio, analog audio, jumper blocks, IDE cable, power supply (from left to right).

SCSI Drives – The Exception

Although the SCSI (Small Computer Systems Interface) bus system offers greater flexibility, it’s also much more expensive. SCSI is only used for workstations and servers. Ultra2 or Ultra 160 SCSIs are typical standards. A SCSI ribbon cable has 68 pins. All SCSI standards have one thing in common: you can run at least seven drives on one adapter. “Wide” models even allow 14 devices to be operated.

It is important to know how it works. SCSI is an open bus system and allows cable lengths of well over a meter. However, the bus must be closed with a terminal resistor at each end, so that the signals don’t reflect. Termination can mostly be activated by a jumper on the last device. LVD cables have their terminator as a plug-on module. The position of the individual devices on the SCSI cable, by the way, is up to you. The drives are distinguished by way of so-called SCSI Ids that run from 0 to 7 or 0 to 15. ID7 is usually the host adapter, 0 or 1 is usually used for the hard drive(s). The rest of the configuration is up to you. Jumpers are used to define the ID address from 0 to 7. In the following example, the manufacturer has named its SCSI address IDs DAS0 to DAS3.

Description of the SCSI jumper block for auxiliary connectors. DAS0 to DAS3 are the SCSI address bits.

Jumper table for setting addresses.

Connector blocks on an SCSI hard drive: power supply, jumper blocks (auxiliary connector), SCSI ribbon cable (from left to right).

In this example, termination can be activated by bridging pins 9 and 10. This is called “Enable SE SCSI Terminator” in the picture.

Safety Notice: The destructive potential of electrostatic

Walking across a floor dragging your feet will create friction, which charges us with energy. Once you stop moving, the soles of your shoes insulate you, but you’re still carrying around a different voltage potential than your environment. Everyone’s felt the sudden shock from a static spark, which is particularly common with plastic floors and thick, rubber-soled shoes. This electromagnetic phenomenon can have dangerous consequences for electronic components. Although the current from a static discharge isn’t very high, the voltage difference may briefly peak at tens of thousands of volts. That much voltage can easily destroy sensitive components such as memory chips.

The most important thing to do before getting down to work is to ground yourself. Ideally, you’ll have an antistatic armband, as used in industry. But unless you’re a real electronics whiz, you’re unlikely to have one. So, try this instead: before you come into contact any of your PC’s components, simply touch something metal (a radiator, the protective contact on a plug or the PC case). This will ground you properly.

Drawing Up a Plan

Before you start the actual assembly, familiarize yourself with the case and components. Unpack all the parts and keep them nearby, but not so close that they interfere. Most cases don’t come with instructions, so you should first check which screws and parts go where, and what each is for – and whether you may have to remove anything from the case before you can install the drives. Get yourself a proper lamp before starting, especially if you work at night. The ceiling light in your workroom is usually not bright enough.

Finally, consider where you want to put each drive. There are only a few rules for drive placement, but valuable ones to follow when in doubt:

• If the PC is under your desk, it makes sense to place the CD-ROM and/or DVD drive as high up as possible so that you don’t have to bend down so far.
• Always check to make sure that the ribbon cable is long enough.
• Some components get warm or even hot when operating. Always make sure that there’s enough air circulating for the heat to dissipate. That’s especially important for modern graphics cards and hard drives.
• If you’re intending to put in two hard drives, make sure that there’s enough room between them. Otherwise, they may overheat, leading to a shortened life span and instability.
• Make sure that neither cables nor other components can get caught in a fan.
• All cables must be run so that no air vents or openings are completely blocked.

This article covered the basics and some practical aspects. In the following article, Building Your Own PC, Part 2: Assembly Step by Step, we’ll describe how to put all the components together to make a functioning PC. Users who only want to swap individual components (upgrade) will also find all the information they need.