Even if you buy pre-configured computers, you should still consider what kind of motherboards you are getting. It is very common today to find a number of the devices, which were formally expansion car, are now integrated into the motherboard. In many cases, the motherboard is smaller and therefore the total cost is reduced. However, this means if you wish to use something other than what indeed motherboard manufacturer has provided for you, you’ll need to spend additional money as well as needed away to disable the device on the motherboard.

The reason the motherboard becomes smaller is that it can “get away with” having fewer expansion bus slots. Since the hard disk controller, for example, is integrated into motherboard, you do not need to use an expansion slot for. If this were a controller for IDE drives, you are less likely to want to buy one your own. However, if the SCSI host adapter is built and, you want to use something more powerful than the one which is provided, have to take up of the main expansion slots with the additional SCSI host adapter.

Another problem motherboard design brings with it is the placement of the integrated controllers. In some cases, I have found the plugs for such devices stuck between the expansion slots. While this does a great job of saving space, it makes it extremely difficult to access the pins. The only way to connect the cable to the pins was to remove all of the cards. However, you had to be extremely careful when ypu put the cards back in so as not to pull a cable off of the pins. Although it is unlikely you will be changing expansion cards every day, the headache and wasted time often negates any benefit of having paid $10 less for the motherboard.

Most were motherboards which I have encountered, with three PCI slots and at least three ISA slots. Some come with either an addition PCI or ISA slot, while some have an AGP slot. However, you can expect to have at least six expansion slots makes between PCI and ISA.

One thing you need to be careful about when shopping for motherboards is whether or not they support your chosen CPU. People do not often have a CPU before they have the motherboard (although I did once), you may have decided on a particular CPU before you buy it and the motherboard.

The days are gone in which you could simply bought a “PC motherboard” and expected to work with your CPU. The technology is changing so fast and there are so many different kinds of CPUs on the market, you need to be absolutely sure the CPU is compatible with the motherboard. Most of the motherboard manufacturers have Web sites with a compatibility matrix. You can find out which CPUs are supported and which clock speeds.

Sockets

One thing to consider when buying in motherboard for your CPU is where you are going to plug in that CPU. Not all CPUs are alike and non-all sockets for the CPUs are alike. As of this writing, nine different socket types (0-8) have been defined.

There area several things to note about this table. First, There was never an officially designated socket 0, but Intel made a line of socket for 486 OverDrive processors which followed the Socket 0 design.

Second, the difference between an in-line and staggered pin layout is simply whether or not the pins line up in different rows.

The inner 169 pins of Socket 2 match those of socket 1, so you can simply plug in a CPU that is normally intended for Socket 1. The only difference is that the outer pins are open.

You will see that Socket 3 is the same size as Socket 2, but has one pin missing and the “keying pins” are in different place. It supports CPUs with either 3V or 5V and the rearranged keying pins help prevent someone from accidentally putting a 3V CPU into a 5V machine.

Socket 4 was for the first Pentiums, but is no longer used. It was followed by the Socket 5, which had a staggered pin layout. Socket 6 had a similar layout to sockets 2 and 3, but was only able to handle the 486DX4.

Finally, we get to Socket 7, which is currently the most common for Pentium based machines. The Pentium Pro CPUs fit into Socket 8.