How to Build Your Custom Computer System

1. The Case:
Cases come in basically three formats. They are the AT, ATX and AT/ATX formats. Some name brand systems have their own configurations but we will not discuss those here. Our intent is to help the home builder complete a system from over the counter parts.

AT format is the most popular and used with most all systems that contain 286 to Pentium based CPUs. ATX format is the newest style of case which supports the Pentium II CPUs and some Pentium based systems. In the future this will be the most used case and is also the one we would recommend that you buy for future expandability. AT/ATX format cases will accept either format.

The name used to describe cases is a misunderstood and sometimes misleading description. Here are the ones that you will see most often from IT Services St. Louis.

Full Tower The standard for use in network servers. These cases usually have 10-13 bays for drives etc. A high number of 5.25″ bays and at least one 3.5″ bay will be seen from the outside of the case. On the inside you will find one to four internal 3.5″ bays for hard drives.
Mid-Tower The most used case for home gaming systems and those with a large number of external drive needs. These cases usually have three to four 5.25″ bays and one to two 3.5″ bays seen from the outside. On the inside you will find one to four internal 3.5″ bays for hard drives.
Mini-Tower The standard for most business workstations and small home systems. These cases usually have two 5.25″ bays and two 3.5″ bays seen from the outside. On the inside you will find one to two 3.5″ bays for hard drives.
Desktop These cases are used, as their name implies, for systems which need to sit on top of desks etc. They make a good base upon which to sit your monitor. This configuration takes up the least amount of space of all the cases mentioned so far.
Slimline The slimline case is a special type which accepts miniature motherboards with special adapters for installing expansion cards. Unless you have the need for a very small footprint case I would recommend staying away from these cases. They are very hard to work on and will only accept a limited number of expansion cards, usually 3-4. Most also require that you use a motherboard which has the video card and sound card built into the motherboard.

There are also a couple of other names you will hear or see. The Mini-Mid Tower, Super-Mini Tower and Mini-Plus are just a few. These case names are used for non-standard sizes. In fact, all of the above refer to the same size case. It is a cross between a mini-tower case and a mid-tower case. They have more bays than a mini-tower but fewer bays than a mid-tower. Some sellers even try to get by with calling these cases mid-towers since you can find them with up to 8 bays which is the same number as some of the true mid-tower cases. Don’t be fooled. The mini-mid tower case is physically smaller than the true mid tower.

When choosing your case you should take into consideration what items you want to install now and items you may want to install in the near future. We say in the near future for a specific reason. If you don’t intend to make changes within the next year or so you may be wasting your money now by getting a larger case than you need. Today’s market shows that new processors and accessories are released so often that a computer system will only stay up to date for about one year. After that time you will need to upgrade your system to be able to run current software or take advantage of the newest hardware available. The introduction of the ATX case has shaken up the home user by requiring a new case to upgrade. In the past we have all been pretty happy to keep our current case and just upgrade the motherboard etc as required. Now we have to buy a new case to accomplish this goal. It is better to go ahead and get this new ATX case now and be ready for those new motherboards in the near future.

The POWER SUPPLY rating is a much over rated item to look for. Sure there is a point at which the power supply is too small. Most consumers look for the largest power supply they can find. If you see a mini-tower cases with a 300W power supply you can bet you will never use its ultimate power rating. There is just no way to get that many items in the case to require that much power. On the other hand if you buy a mini-tower case with a 180W power supply you may be limited. Our recommendation is to limit the lower end to a 200W supply and the upper end to a 250W supply. As you move up in size we recommend that you increase the power requirements by 50W for each standard size. In other words a mid tower case would be 235-300W, a full tower would be 300-350W. The desktop and slimline cases will work quite well with the 200-250W power supply.

The number of DRIVE BAYS is an important consideration. Nothing is more frustrating than to find that new case you just bought will not hold all of your drives. Make sure you know what your current requirement is and add at least one bay for future expansion. In the normal system you will require at least one 5.25″ bay for your CD-ROM drive and two 3.5″ bays for your hard drive and floppy drive. Since most all motherboards will now support up to four hard drives we would recommend at least two internal bays for hard drives. External 3.5″ bays needed would be at least two in most cases. This would allow for two 3.5″ floppy drives for coping one disk to another. Be aware that you may want to add a tape backup system, zip drive or other items in the near future. This would increase the number of external 5.25″ bays you would require.

EXPANSION SLOTS are another consideration. Although most cases come with a standard of 8 expansion slots there are some with less. You will notice on your motherboard that you will have seven to eight slots for expansion cards. This is also the standard for most motherboards. Therefore you would look for a case with the same number of slots plus one if possible. The additional expansion slot would give a little leeway for future motherboard changes. In any event do not buy a case with less than seven expansion slots. They fill up fast when adding modems, sound cards, etc.

Last but not least is the quality of the case. As the saying goes “you get what you pay for”. Buy the highest quality case you can afford. The differences are usually apparent. The high quality cases have high grade metal with rolled edges and a UL and FCC approved power supply. Some of the less expensive cases have sharp edges on the metal resulting in cut fingers and wrists. Not a very good feeling when installing your components. These cases also have inferior power supplies. They are not UL or FCC approved for use and usually have a high rate of failure. When in doubt ask your supplier and get the best for your money.

Next week we will cover motherboards. What format to use, what frequency range you need and the best chipsets to look for when buying your new motherboard. We will also cover the installation of the motherboard into the case.