Final assembly is usually the least time-consuming part of a build. Component selection may require days of consideration, and finding the "best" seller can take up the better part of a day, but plugging connectors and inserting screws shouldn't take more than a couple hours, even for the most inexperienced builder.
An average person familiar with a few simple hand tools could assemble a complete system in less time than it takes to read this guide, but figuring out what he or she may have done wrong could slow things down significantly. Phobias aside, you're unlikely to damage your hardware or yourself if you follow a few very easy precautions, and we hope this final segment will eliminate hours of post-build troubleshooting.
First Precautions
Nothing creates a sinking feeling more effectively than damaging a component before the build is finished. Major concerns include electrostatic discharge, dropped parts, and breakage caused by force fitment or scratched circuits.
Electrostatic Discharge
An accidental electrostatic discharge (ESD) could destroy a component, a fact that's caused many building guides to exaggerate this danger. In all truth, few experienced custom PC builders take more than the most basic precautions against ESD; even when it does occur, it's likely to follow the component's ground plane rather than zap its most sensitive parts.
The most basic precaution is to occasionally touch a ground, such as a large metal office desk or the metal case of a plugged-in system, to discharge your body. Additional ESD risks come from the use of carpeted workspaces and extremely dry environments, so another level of protection may come from the use of an antistatic mat under the chair and a humidifier for extremely dry rooms. Grounded wrist straps are an over-the-top method of protection rarely used outside of production environments, yet the extra-cautious will attain peace of mind when wearing one.
Fallen Components
It seems easy to prevent in theory, but damage from falls is a far more likely cause of broken components than the previously mentioned ESD. Hard Disk Drives are often dropped during installation and other parts can be easily knocked from a desk. Reducing drop distance is as easy as moving work away from the edge of a desk, and reducing damage from parts getting knocked to the floor is as simple as leaving them in the box until they're ready to be installed.
Assembly Damage
Most components require a small amount of force to seat the connector, but a few don't. We'll cover the specifics for each part as we install it.
For the last ten years, socketed processors have followed a common theme: an arrow on one corner of the CPU aligns to another arrow on the CPU socket. This is the first method manufacturers use to assure proper orientation, but AMD and Intel also use missing pins with blocked socket holes to further prevent improper installation.
CPU pins are easily bent, so a truly dysfunctional builder could successfully force the CPU into the socket the wrong way while smashing pins in the process. With the tension level released as shown, the CPU should literally drop into the socket under its own weight, with no force applied. These are known as "Zero Insertion Force" (ZIF) sockets.
After checking to make sure the CPU is fully inserted, press the tension lever into the horizontal position to lock it in place.
LGA Processors
In addition to being marked with an arrow, pinless processors have edge notches to prevent incorrect installation. A load plate holds the CPU tight against its contacts, using a locking lever to apply the load.
After making sure that the CPU is correctly installed as shown above, drop the steel load plate over the CPU and rotate the wire clamp into its locked position.
Installing The CPU Cooler
Thermal Paste
Thermal Interface Material (TIM) fills tiny spaces between the CPU and its cooler to assure optimal heat transfer. Most factory-supply coolers come with a stiff TIM pre-applied that becomes soft when heated by the CPU, but other coolers will require the use of thermal transfer grease or paste.
There are several ways to spread thermal paste, but dabbing small dots onto the contact area is probably the least wasteful. Though many well-read enthusiasts would panic at the "mess" seen in the left photo below, applying and removing the CPU cooler proves adequate spreading. A small additional amount will squeeze out from the edges over time.
Other methods, such as spreading the paste with a smooth piece of plastic, are often recommended by paste manufacturers, resulting in more paste being stuck to the spreading apparatus than the CPU. The concept is to provide a thin, even layer of paste on the CPU without creating an over-thick heat barrier, but modern pastes are usually thin enough to prevent this problem.
Excess paste will squirt out around the edges of the CPU, so it's important not to apply so much as to create a mess.
Clip-On Coolers
AMD still uses metal clips to attach its retail-boxed cooler over the CPU. With the cooler in position, slip the non-levered end over the corresponding plastic hook, then repeat the process on the levered end. Finish the installation by flipping the lever to apply pressure.
Pin-On Coolers
Intel introduced push-in pins to CPU cooling with its LGA775 package. Installation requires pushing each pin into the corresponding motherboard hole until a "click" is felt or heard.
Twisting the top of the pin ninety-degrees counterclockwise unlocks the spring pressure, allowing the cooler to be removed. Because a counter-clockwise twist defeats the latching mechanism, one should check that all pins are properly twisted fully-clockwise before attaching the cooler.
Screw On Coolers
The biggest problem with Intel's pushpin cooler mounting method is that it puts a lot of strain on four points of the motherboard. Several manufacturers require a support plate to be mounted under the board to properly distribute the load; these coolers are usually attached with screws.
Because the support plate must be placed behind the motherboard, these coolers should be mounted before the motherboard is installed into the case.
Installing The Power Supply And Motherboard
Preparing The Case
Most cases support a range of motherboard sizes, each with a few different mounting points. These points are meant to connect a layer of the motherboard called the "ground plane" to the case's mounting tray, reducing signal crosstalk due to radio frequency interference (RFI). Thus, the mounting points are grounded.
Solder points around mounting holes ground this motherboard to the chassis through brass standoffs, which are included with the case.
Misaligned mounting points could contact a "hot" trace on the motherboard's back side, so case manufacturers usually make them removable via brass spacers called "standoffs". It's important to observe the motherboard's mounting hole positions and place a standoff in each corresponding tray location. A mistake made here could potentially damage the board, but the most likely result is just a system that simply refuses to "power on".
Standoff locations must exactly match the mounting holes of the motherboard.
Most motherboards use a custom port arrangement and include a customized rectangular cover plate that snaps into a standardized rectangular hole on the case. Cases typically include an old-fashion standard plate that must be snapped out before inserting the new, custom one.
Note that the upper tabs hang down because the cover plate usually arrives in a semi-flattened state. These need to be bent approximately ninety-degrees from the surface to prevent them from blocking nearby ports during motherboard installation. The left tab in the photo below has been bent to the proper orientation.
Attaching Components
The power supply is usually easiest to install prior to motherboard installation. It's typically held in place with four coarsely-threaded screws.
Recheck standoff positions before inserting the motherboard at a slight port-first angle, aligning ports with cover plate holes while guiding the motherboard until it rests flat against the standoffs. Grounding tabs on the port covers will typically push the motherboard out of position by approximately half the hole's width, but the board should be easy to push into place. Align one hole perfectly with the standoff and affix a screw, then push the board into alignment for a second hole before tightening the second screw. The first two screws should prevent the board from twisting out of position while installing the remaining screws.
Installing RAM And Cards
RAM is keyed so that it only fits one way. Check to make sure that the notch in the module's contact area aligns with the slot's "key", and press each module into the slot until a "click" is heard or felt from the latches. Fully seating modules may require a relatively significant amount of pressure.
RAM cannot be fully inserted backwards, as a misaligned key prevents it.
Our configuration called for a pair of modules in corresponding slots, to enable "dual channel mode". Check your motherboard manual to see which slots should be used for this performance enhancing feature.
Though our motherboard included onboard graphics, we chose to use a PCI Express graphics card for enhanced performance. The card is inserted until a latch on the slot engages the card's "hook". These latches are present on most PCI Express x16 and AGP slots, but are not found on lower-bandwidth interfaces, such as PCI and PCI Express x1.
As with other cards, a case screw or quick-release latch secures the top of the card's metal bracket at the opposite end.
Installing Drives
Drives have traditionally been secured in place with screws, usually with a fine thread for external drives and coarse thread for internal hard disk drives. External drives typically slide in from the front, while internal drives slide in from inside the case.
Several manufacturers offer screwless installation, using either drive rails or sliding latches that engage with screw holes. Our Case Reviews highlight several designs.
A few notes about jumpers on Ultra ATA and ATAPI drives. First, the "Cable Select" setting works well with most motherboards and drive combinations, and the "last drive" (the one at the cable's end) becomes Master. Second, for manually configured "Master/Slave" combinations, the end drive should be Master. Third, Western Digital Ultra ATA drives usually have different settings for "Master" than for "Single", and the "Master" setting will typically malfunction if there's no "Slave" on the same cable.
Connecting Cables
Motherboard Cables
The latest ATX standard uses a 24-pin connector previously found on server-sized EPS power supplies, but most motherboards don't require all 24 pins. The below example shows how a 20-pin plug fit into a 24-pin socket; the wide latch is designed to work with either 20-pin or 24-pin plugs.
Reasons for 24-pin power include added amperage supplied to PCI Express slots compared to older interface standards. While most cards won't "overdraw" a 20-pin connector, graphics card makers have suggestions for minimum available power.
The 4-pin or 8-pin ATX 12V connector satisfies the electrical demands of the CPU. Formerly known as the "P4" power connector, Intel added it to supplement its inefficient Pentium 4 cores, but it was adapted to AMD motherboards as well. 8-pin versions are a later development meant to address phenomenally power-hungry Pentium-D and Prescott core Pentium 4 processors, but current AMD and Intel processors are efficient enough to once again work from 4 pins. Most 8-pin boards will work with both 8-pin and 4-pin power, as the connectors are cross-compatible.
Also seen in the photo above are a 4-pin CPU fan power connector, and the Front Panel Audio connector. 4-pin fans are designed to use a new pulse width modulation automatic speed control, but the connectors are once again cross-compatible with 3-pin fans. Check your motherboard manual for instructions on the Front Panel Audio connection.
The case's power switch and indicator light, reset switch, and hard drive light are usually connected at the motherboard's lower front corner. LEDs pass current in only one direction, and "positive" pins indicated by a "plus" sign below normally connect to the colored wire on each lead. A black or white lead wire usually indicates "negative" or ground state.
USB connectors have been standardized for several years. The missing pin location is blocked by most front-panel USB connectors to assure that the connector is polarized correctly. A reversed connection would damage the motherboard, so 4-pin, 8-pin, or single-row internal break-out cables require special care. The missing pin indicates the negative/ground end of the connector.
Device Cables
Floppy drives may be fading into history, but one myth has stuck around nearly since the beginning: the "red stripe" indicating pin 1 on the data cable does not always face the same side as the power connector. As seen below, both drives have pin 1 on the "left" side as seen when facing the connector, but the top drive has the power connection on the "right" side when viewed from this same perspective. The photo below also shows the data cable orientation for all drives we've tested: pin one is on the same side regardless of the locations of other connections.
Most floppy cables are now "keyed" with a block below the connector, but many floppy drives such as the bottom one in the photo above are designed to defeat this protection.
ATAPI and Ultra ATA drives have pin 1 on the "other" side of the connector as seen when facing it - on the right in the photo below - it's been many years since we've seen a nonstandard drive. A key is located on the top of all 80-conductor ATA cables to prevent upside-down insertion.
Floppy and ATA drive power connectors are keyed to fit one way. Of these two connector styles, floppy power is easiest to force on the "wrong way" and should be visually inspected to ensure proper placement.
Serial ATA power and data cables are keyed on the sides as seen on the drive below. Some Serial ATA drives are also able to accept older 4-pin ATA power connectors - the sticker warns that builders should chose either serial ATA or "legacy" power, but not both.
Some PCI Express graphics cards require more power than the slot is able to provide, and use the 6-pin input connector shown below. This connector must never be confused with 4-pin or 8-pin motherboard power, as its polarity is the opposite of those!
AGP cards that required additional power used a 4-pin connector as described for floppy or Ultra ATA drives.
Final Word
No system is complete without software, and most operating systems come on a bootable CD. The system's boot order can be selected in the motherboard BIOS under the "Advanced BIOS Features" menu, and should be set to boot from CD first. If the ATA interface used comes via an add-in controller, the menu may name the drive instead.
Single drives needed to install Windows XP should always have their controllers set to non-RAID mode, so that Windows Setup can address these using generic "Standard IDE controller" drivers. Advanced configurations such as RAID will require a driver floppy to be inserted, and the user to respond to the prompt "Press F6 to load third party SCSI or RAID drivers".
Further BIOS tips and tricks can be found in our BIOS for Beginners article.
We hope that this series has made your build a complete success, but if it hasn't, members of our Forumz eagerly anticipate your technical questions.
