Introduction to Motherboards

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The motherboard is an extremely important part of a computer system. Not only does it determine what you can and can't have in your system, it also has a big impact on performance. So, choose carefully, and get the best motherboard you can afford.

What Does A Motherboard Do All Day?

All the other devices in your PC such as the microprocessor, memory, drives, multimedia cards, printer, and monitor all "plug"

into the motherboard in one way or another. Once connected to the motherboard, each device is able to send data to the main memory. Main memory is a holding ground for the data and instructions that the CPU needs in order to complete tasks. When the CPU requests data, the memory locates it, then sends it over to the CPU via a pathway on the motherboard called the system bus. When the processor finishes processing the data, it sends the result back to the memory, which in turn sends it back to the device that needs it. The motherboard's chipset coordinates and controls the speed and timing of these interactions.

On the right is a diagram of a motherboard. Notice it is made up mostly of sockets, slots, connectors, and ports. The two primary exceptions are the chipset and the BIOS chip, which are built into the board.

The chipset is the most important part of a motherboard; it is largely responsible for the stability and performance of the board, and it determines which features are supported and which are not. Some well known motherboard chipset manufacturers include Intel, Via, SiS (Silicon Integrated Systems Corp.), SuperMicro, Ali, and AMD. Nvidia has recently entered the core logic market as well.

The BIOS (basic input/output system) is responsible for booting up the computer when you first turn it on. It also helps control the flow of data between the operating system and hardware devices. Traditionally, the BIOS was on a ROM (read only memory) chip to ensure that its instructions would never be erased. Most modern motherboards now have the BIOS on flash memory, however, which enables the BIOS to be "flashed" (updated) if desired.

What CPU Will You Be Using?

If you already know what CPU you'll be using, great. If not, start there. Think about what type of computer you want. Are you a gamer or someone who does a lot of image editing? If so, you may want a higher-end CPU such as an Intel P4, or an AMD AthlonXP. If you primarily use your PC for Microsoft Office and surfing the Internet, you may want an Intel Celeron or an AMD Duron.

Deciding on a CPU will help you narrow down your motherboard choices quite a bit. A motherboard will only support specific types and speeds of processors. For instance, a motherboard designed for an Intel P4 will not support an Intel PIII, and a motherboard designed for an Athlon processor up to 900MHz, will not support a 1400MHz Athlon. Also, it's important to understand that a motherboard will support either an Intel processor or an AMD processor, but not both. Intel and AMD (Advanced Micro Devices) are the major two manufacturers of processors.

In addition, you must purchase a motherboard that your CPU can physically connect to. The motherboard's slot or socket is where you will "plug in" your CPU. (See the CPU socket on the diagram.) Different CPUs come in different types of packaging, which only fit into certain slots or sockets. Therefore, if you know what type of slot or socket you need, you can eliminate all the boards that don't have it.

Before you purchase a motherboard, we urge you to contact the board's manufacturer and double check that it is definitely compatible with your CPU. Accidentally purchasing a board that doesn't support your CPU will put a major damper on your project.

The following is a list of available CPUs and the socket or slot type they require. Notice that the latest processors use sockets rather than slots.

CPU	Compatible Socket type
Intel PII	Slot 1
Intel Celeron	Slot 1 (old) or Socket 370 (new)
Intel PIII	Slot 1 (old) or Socket 370 (new)
Intel P4	Socket 423 (old) or Socket 478
AMD K6-2	Super 7
AMD K6-3	Super 7
AMD Duron	Socket A
AMD Athlon	Socket A
Via CIII	Socket 370
Via Cyrix MII	Socket 7

*Note: It is also possible to purchase a converter card that enables an Intel PPGA or FC-PGA CPU (for Socket 370) to connect to a Slot 1 motherboard.

Memory

As mentioned earlier, the CPU and main memory constantly exchange information in order to accomplish tasks. The information travels between them over a data pathway called the system bus (also referred to as the frontside bus (FSB)). The speed of the system bus has an impact on a computer's overall performance, as does the speed of the main memory. The memory's speed refers to how quickly it can find the data requested by the CPU.

When shopping for a motherboard you'll notice that different motherboards support different types, speeds, and form factors of memory. Currently, the most widely used memory form factor is the DIMM (dual inline memory module). And the most commonly used type of memory is SDRAM (synchronized dynamic random access memory) in speeds of 100 (PC100) or 133MHz (PC133).

However, DDR (double data rate) SDRAM has entered the picture. DDR SDRAM takes advantage of both the rising and falling edge of the clock cycle, whereas regular SDRAM only uses one edge. This makes DDR SDRAM twice as fast as SDRAM. That doesn't mean your computer will be twice as fast, but it can mean significant performance improvements. Currently DDR SDRAM comes in the following speeds.

To clarify further, PC1600 is designed for a 200MHz system bus, PC2100 is designed for a 266MHz system bus and so on. Using DDR SDRAM in a system with a 100 or 133 MHz system bus won't yield any performance improvements. Also it won't fit.

Integration Anyone?

Certain components of a computer can either be built into the motherboard or bought separately in the form of cards and plugged in. In general, purchasing a motherboard with integrated components will save you money, PCI slots, and probably time. However, there are down sides too.

• Video : You can save money by purchasing a motherboard with integrated video, but beware that the video quality will be low-end*. Many boards with integrated video don't have an AGP expansion slot, which means you'll be stuck with low-end video until you upgrade your motherboard again. However, there are some boards available that do have both integrated video and an AGP expansion slot. That gives you the option of overriding the integrated video with a video card later on.
• Sound : Purchasing a board with integrated audio can also save you money. The sound circuitry has traditionally been low-end*, although more and more exceptions to that are occuring. Integrated sound is more popular than integrated video, probably because even cheap audio circuitry offers decent quality sound. If you think you may want better sound in the future, however, make sure the motherboard allows the onboard audio to be disabled.
• SCSI : SCSI (Small Computer Systems Interface) is one of the two interface alternatives for drives. SCSI is a more technologically advanced interface than EIDE. SCSI offers a higher bandwidth, and is the better choice if you'll be connecting more than four drives. However, most mainstream users still choose EIDE. EIDE is less expensive and easier to configure. In addition, it comes standard on most motherboards.

  If you choose SCSI over EIDE, it is less expensive to have SCSI integrated into the motherboard, than to purchase a SCSI expansion card. On the other hand, if you opt to purchase a board with integrated SCSI, the next time you want to upgrade to a new motherboard, you'll have to pay for SCSI again, rather than just transferring your SCSI card to the new board.
  

• RAID : Integrated RAID (Redundant Array of Independent Disks) will enable you to set up a RAID configuration. RAID configurations are most commonly used in servers, however PC users are starting to take advantage of them too. A RAID configuration consists of two or more hard drives recognized by the operating system as a single hard drive. When the user makes a request to "save" data, it is saved to all hard drives, thereby automatically making a back up. In addition, data can be read from both hard drives simultaneously, improving performance. However, there are more than 10 types of RAID, some which vary from this definition. Integrated RAID will save you some money, but you can't take it with you when upgrading to a new motherboard.
• LAN (Local Area Network) : Integrated LAN will save you a PCI slot and some time, but probably won't save you much money since network cards are rather inexpensive. Also, when you change motherboards, you won't be able to transfer integrated LAN to the new board. Nevertheless, LAN is a popular feature to integrate, perhaps because it just makes things a little easier for the user.

Basic Features

Everyone has different motherboard requirements depending on the type of system they want. However, the following is a list of basics we believe most people will benefit from having. Refer to the motherboard diagram above for a visual representation of the following features.

• ATX or MicroATX Form Factor : Form factor refers to the size and layout of your motherboard, as well as the type of case and power supply you need. Currently, most motherboards are ATX. Therefore, if you go with ATX you'll have a lot more options. (The motherboard in the diagram above is an example of an ATX board.)
  
  

  The second most popular form factor is MicroATX. MicroATX boards are smaller, which makes them more difficult to tweak or plug things into. In addition, there aren't as many sockets for memory, or expansion slots. On the other hand, they are usually less expensive, and a MicroATX case will save you space. A MicroATX board can also be used in an ATX case if needed.
  

• ATA/66, ATA/100, ATA/133 (EIDE) : As mentioned in the SCSI section, SCSI and EIDE are your two drive interface options. EIDE (enhanced IDE) comes standard on most motherboards. However, different motherboards have different grades of EIDE. These days EIDE comes in four different bandwidths: 33MB/sec (ATA/33), 66MB/sec (ATA/66), 100MB/sec (ATA/100) and 133MB/sec (ATA/133). Getting a motherboard with ATA/133 will allow you to use ATA/133, ATA/100, ATA/66, or ATA/33 drives, because it is backward compatible. Unless you have an ATA/33 hard drive that you never plan to upgrade, don't opt for ATA/33. In addition, currently ATA/133 and ATA/100 don't offer much performance benefit over ATA/66, however, as hard drive speeds increase these higher bandwidths will become more useful.

  *Note: the ATA specification is also commonly referred to as Ultra DMA.
  

• An AGP Slot : Most new graphics cards are designed to use AGP (accelerated graphics port) technology. AGP provides a fast data pathway between the video card and the computer's main memory. Formerly, most video cards were made for the PCI bus, which the AGP has surpassed in terms of speed and performance. PCI video cards are still available, but an AGP card is preferable. Choose either AGP1x/2x, AGP4x, AGP8x or AGP Pro. The faster the slot is, the more bandwidth you have for transfering data from the rest of the system to your graphics card. Note that sometimes AGP slots require video cards of a certain voltage. For instance, many Intel boards have an AGP 4X slot that only supports video cards that are 1.5V. This means an older 3.3V video card would not be supported.
• PS/2 : This is the most common type of connector for a keyboard and mouse.
• Parallel Port : This is the most common type of port for your printer. Some scanners also use a parallel port connection.
• USB Ports ( 2 minimum ) : USB 1.1 (universal serial bus) is a data pathway between main memory and peripherals that require a slow to medium data transfer rate such as joysticks, keyboards, and scanners. USB supports plug-and-play, which makes connecting plug-and-play equipped devices very easy. With plug-and-play a computer is supposed to be able to immediately recognize a newly connected device without the user having to configure anything.

  In addition, recently USB 2.0 has come to market. USB 2.0 offers up to 40% more bandwidth than USB 1.1, and is even slightly faster than FireWire (IEEE1394). This makes it more viable for devices such as external hard drives and CD-RW drives. In order to take advantage of a USB 2.0 port, however the device you wish to connect must also support the 2.0 specification.

• PCI Slots (4 minimum) : Even if the PCI bus is no longer ideal for video cards, it is still used for other types of expansion cards such as sound cards, SCSI host adapter cards, IEEE 1394 (FireWire) cards, and network interface cards.
• DIMM, DDR DIMM, or RIMM Sockets : Make sure the motherboard can support the amount and type of memory your system needs. Motherboards that support DDR memory are currently very popular because DDR memory offers twice the bandwidth of standard SDRAM.

  As far as amount of memory, most systems require at least 64MB, and 128 is becoming pretty standard. If you want to use your system for graphic arts, publishing, and multimedia you'll probably want 256MB or 512MB of memory for optimum performace. It's a good idea to leave yourself room for more memory should you need it.If you are building a new system from ground up I would advise 1GB of memory.

Special Features

There are numerous special features available these days, and new ones appearing all the time. The following are a few of the more common ones.

• Dual CPUs : Some motherboards support two CPUs. Dual CPU systems are well suited for small graphics workstations or servers.
• Dual BIOS : Dual BIOS technology is nice because if your primary BIOS fails for any reason the second BIOS will enable you to get your system back to an operating state so you can fix the problem. Only a few motherboards have this feature. (Gigabyte is one manufacturer who offers it.)
• IEEE 1394 (FireWire) Port : IEEE 1394 is a high performance serial bus. Currently, it is primarily used with peripherals requiring high, real time data transfer rates, such as video devices. Only one port is needed because up to 65 IEEE 1394 compatible devices can be daisy-chained together.
• Serial ATA : This is a new standard for connecting Hard Drives. The cables are physically much thinner than the old wide IDE cables, and while the transfer speeds are 150MB/s or faster, it is also supposed to be more reliable than the old IDE. Remember, Serial ATA requires Hard Drives to support this feature or you will not be able to connect it.
• Jumperless : Motherboards have jumpers or dip switches that are used for adjusting the system's clock speed. Many computer users will never alter their system's clock speed, but some individuals may want to. Generally these users are interested in overclocking. Overclocking is the practice of increasing the system clock speed in order to run the system bus and CPU at a higher speed than the manufacturer has recommended. Overclocking will void your CPU's warranty, and it could cause serious damage to your entire system. However, for those interested in overclocking anyway, a jumperless board is handy. Rather than having to open up your case and adjust the jumpers or dip switches by hand, a jumperless board enables a user to adjust clock speed via software.
• Adjustable AGP/PCI Speeds : Again, adjustable AGP and PCI speeds is something that will only be useful for overclockers. When the speed of the system clock is increased, the speed of the AGP and the PCI bus are also automatically increased, which can cause problems. Adjustable AGP and PCI speeds can eliminate those problems.
• CPU and Motherboard Temperature Monitor : Again, for overclockers. One of the primary dangers of overclocking is too much heat. Temperature monitors help overclockers prevent heat problems. Also Everest Home is a very good and I might say free program that will monitor CPU temperature along with many other things. A very good program.

Conclusion

Once you have narrowed down your choices to a few motherboards, investigate the chipsets they use. Some chipsets have better reputations than others.

In addition, it's a good idea to purchase a motherboard built by a reputed manufacturer; just like a house, you don't want to build your PC on a poor foundation. Some well-known motherboard manufacturers include Asus, Abit, Intel, Microstar (MSI), SuperMicro, Tyan, and Gigabyte.