MICRO CENTER: COMPUTERS & ELECTRONICS
Instore Clinic

Choosing a Case

Computer cases come in many shapes, sizes, colors and levels of functionality. Before purchasing a case you'll want to consider several things.

Functionality vs. Aesthetics
End users tend to choose a case based on outside appearance and price. Computer experts tend to choose based on functionality and brands. Quality of most cases that would be considered aesthetically pleasing tends to vary, since much of the styling is done by plastic shells over a simple metal box. Check the floor models whenever possible to avoid unpleasant surprises.

Power Supply
The power supply is one of a few PC components that has moving parts (a cooling fan or fans), and a possible point of future failures. Therefore, choosing a case with a reliable power supply is very important. The wattage of a power supply is likely less important than its reliability. 400W is more than enough for the majority of systems running today. 450W-500W is necessary when multiple hard drives and optical drives are used in conjunction with high end video or other components. Industry standards for measuring the reliability of a power supply (or most other PC components) do not exist. We recommend staying with major brands such as Antec.

Cooling
A case fan (or fans) is highly recommended! With the modern processors used today it is important to deliver cool air to hot components such as processors, video cards, and hard drives. Failure to do so can result in decreased stability and longevity of a system, especially since the failure of a power supply fan can go unnoticed for weeks in a system until the power supply fails or shuts down from overheating. High temperature is one of the worst enemies of all computer components! A front case fan should pull ambient air into the case, while a power supply fan moves hot air from inside the case out. This creates a flow of air across the CPU and helps maintain the temperature inside the case at a relatively low and constant level. Top or rear case fans should push hot air out of the case. Side panel fans (usually positioned near the CPU assembly) should be mounted to pull cool air into the case where it is needed most. A dual fan power supply is recommended when using modern AMD Athlon/XP/64 processors or Intel Pentium 4 processors. The second fan on the power supply helps quickly move hot air away from the processor's heat sink fan combination.

Ease of Use
A roomy case that is easy to access and does not have sharp edges should be on your list. To be fair, the manufacturers are doing much better in removing sharp edges and making strong, attractive cases. But keep in mind, that manufacturing a case out of thinner sheet metal, having straight, unrolled edges, no reinforced folds or framing, and using standard screws (or pop-rivets) are simple ways to keep the cost down. If you are the type of person that is always changing something in your system, then investing in a case that uses time saving features such as thumb screws, spring-locked covers, removable motherboard tray and snap-in drive rails.

Form Factor and Compatibility
Matching the motherboard size specification to the case means that the mounting posts either line up or can be placed to match the holes in the motherboard and there is adequate room to install it in the case.

  • ATX. Almost all motherboards today are ATX or some variant thereof. ATX motherboards are typically 12" x 9.6" or slightly smaller. The most common size of case used to house an ATX motherboard is a Mid-Tower case. If a case supports ATX then it should also work with MicroATX and FlexATX motherboards.
  • E-ATX and Full ATX. Typically found in server cases such as full towers, cubes, and rack mounts, the size of these boards range from 12" x 11" to 12" x 13". If a case supports this size then it should also support ATX, MicroATX, and FlexATX.

Design
Some people like a case that has a slide out side panel, while others like a connected top and cover. Some people like having a slide out motherboard tray, while others prefer a very roomy case to install the motherboard to. We feel that each of these design elements has their pros and cons and that it's largely a matter of personal preference.

Case Material
Steel cases are inexpensive, but heavy. Aluminum cases are much lighter than steel cases, but tend to be much more expensive. The light weight makes it a popular choice among people who move their PCs around very often, such as LAN party fans. Some people believe that aluminum cases have slightly better cooling than the steel ones. While aluminum cases may have a more modern and exotic look than steel cases, they have a drawback of being structurally weaker than steel and more prone to surface scratching and damage.

Noise
Computers have very few moving parts except for fans and drives. The optical drives typically only run at full speed when accessing data, installing, or sometimes burning media. The same is true of floppy disks, in that you only access them to load or save data. The hard drive generally rotates whenever the computer is on, although power management may turn it off during periods of inactivity. Fans on the other hand, run all the time. Fans on the CPU, fans on the case, fans in the power supply. How the fan is mounted, the size and speed of the fan, and where the fan is located all contribute to system noise levels. Fan speed control kits, thermal sensors and pc-health monitored fan control can reduce the overall system noise during normal operation. Reinforced or sound-dampening construction can make the difference between quite operation and a noisy system.

Vibration Transfer Control
In thin steel cases, aluminum cases, and some of the ultra low cost models, vibration can become a problem. Vibration Transfer can happen if a piece with moving parts (such as a fan, hard drive, power supply or optical drive) is screwed directly into the case. In severe cases this vibration can be transmitted into the side panels which case then act as noise amplifiers (think steel drums).

As a rule of thumb, the thicker the case is, the less likely this is to be a problem. Thicker materials tend to absorb vibration rather then transmit it. High quality cases will usually have a thick drive mounting frame. This increases stability and reduces the possibility of transfer. Another approach to this is to use plastic or another substance as an intermediary between the two mounting surfaces. To that end, a large number of cases now use plastic fan mounts instead of traditional fan mounting screws. Fans tend to be a bigger source of vibration then drives.

Drive Bays
The number, position and size of the drive bays may be an important factor when selecting a case. How many optical drives do you want? Do you need a floppy drive or bay-mounted memory card reader? (Many cases only have a single 3 1/2" drive bay opening.) Another factor you may run into when starting assembly is positioning your drives so that the data cables can reach, or getting power-splitter cables to connect the drives to the power supply or to reach other additions like lighting kits.

DIY Mods
(Do It Yourself Modifications) Some cases are more modification friendly then others. If you are thinking about purchasing a case and "modding" it then we recommend that you look for a case that has solid metal panels (either metal or aluminum) instead of plastic or a plastic/steel mix. These types of panels are easier to alter. Also it is better to have separated sides and top instead of joined sides and top, joined sides are hard to alter. For top window or "blow-hole" mods it is best to find a case that uses screws instead of bolts to hold the top of the case on, and to use a case that has a flat metal top vs. a curved plastic top.

Special Features
Once you go beyond basics, the case manufacturers are trying to get your attention with a diverse set of enhancements, many of which sever no real purpose other than to look cool. Some of the case enhancements include thermometer display panels with sensors that you can place under the CPU or next to a hard drive. There are LED illuminated case fans, ultraviolet reactive case fittings, and light-up doors or front panel light shows. There are concealing drive bay doors that hide the ugly beige or black optical drive (when it is closed.) And of course, there are the stylized front and side panels of alien or demonic design.

Rail
Snap-on drive rails make installation quick and easy.

Computer case with rails
Most cases have holes to set the standoffs where they match the holes in your motherboard. Removable trays make installation easier, but add weight. Watch out for cases that have fixed mounting posts, if they do not match your motherboard form factor, you will not be able to use the two together.

Case standoffs should be installed to exactly match the holes in the motherboard. Standoffs support the motherboard, and position it to line up with the rear slots and case openings. Nylon standoffs can be used if there is a possibility of shorting out the circuit board; they also make for fast snap-in installation, although removing the board later can be a challenge.

Thumbscrews
Thumbscrews make accessing the inside of the case quick and easy. Cases may also have spring-lock catches, or other quick-release handles or tabs. These case styles still may use thumbscrews to secure the panels from vibration or torque during transport.

Understanding Tech

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