SATA 2 vs SATA 3

SATA is a standard used to connect devices like hard drives, solid state drives, DVD drives, etc. to the motherboard.

SATA 2 is rated to run at 3 Gigabits per second. SATA 3 doubles that at 6 Gigabits per second. Realistically, SATA 2 can only achieve 300 Megabites per second, whereas SATA 3 can hit 600 Megabites per second.

Hard drives rarely ever reach the 300 MB/s limit of SATA 2 do to the limitations of their spinning platters. However, solid state drives have no moving parts and have reached speeds far above 300 MB/s. As SSD's continue to become faster, the need for faster SATA standards will continue to grow.

Buying a Power Supply

The main job of a power supply is to convert the power from your wall from AC (Alternating Current) to DC (Direct Current). Power supplies will advertise what they're rated to handle. A smaller power supply will be more or less then 250 watts. I try to shoot for 550~800 watts. This is normally a pretty safe range. It's best to buy a power supply that can handle a little more than what you're going to make it do. People who buy larger power supplies than this are probably gamers who are using multiple video cards. Video cards use a lot of power depending on what you get. The video card's details should tell you the minimum amount of watts needed.

Check the types of connectors the power supply has. Most motherboards use a 20+4 pin as the main connector. You may also want a few PCI connectors for video cards. A small video card won't need any connectors because the motherboard can supply all the power it needs. The larger the video card gets, the more PCI connectors they'll need. A huge video card may need up to two 6+2 pin connectors. A video card may say it needs a 6 pin connector. A 6 pin or a 6+2 pin will work for this. 12 volt rails are there to provide a dedicated power supply to the CPU. Some other cords it should come with are SATA connectors (to power the CD drive and hard drive) and some peripheral connectors.

It a good idea to buy a power supply that is energy efficient certified. Nobody wants to pay for energy that's going to get wasted. Here's a list of the energy efficient standards. Make sure your power supply is at least one of these.
80 Plus = 80% efficient
80 Plus Bronze = 82~85% efficient
80 Plus Silver = 85~88% efficient
80 Plus Gold = 87~90% efficient
80 Plus Platinum  = 89~92% efficient

Another optional convenience is modular cabling. This has no impact on the performance of the PC. Modular cabling lets you choose which cords you want to plug into the power supply. This is much nicer than having all the unused cords looking like a mess inside your computer.

Out of all the parts you buy for your computer, it is most important that you get a reliable power supply. It's one thing if a video card goes bad or an optical drive breaks. If a power supply fails, other parts could go down with it. Always make sure the power supply you buy has a good reputation. I normally pay $60 or more so I can have a power supply that I trust. You can easily find cheaper but it is not worth the risk. These are things to consider when buying a power supply.

How to Find a Good Hard Drive

A hard drive is one of the easiest computer parts to learn about. In short, it's where everything is saved on the computer! Now for the longer explanation.

The amount of space that is on a hard drive can range from a several gigabytes to a few terabytes. You can learn more about these terms here. A typical size nowadays is around 250 gigabytes or higher. I usually try to aim for 500 gigabytes or more. Is space all that matters with a hard drive? Not exactly. There are other big factors to consider that affect the performance of the computer. We'll look at some of these.

Above is a hard drive I found that I would consider an excellent choice. This hard drive was made by Western Digital. This model claims to have 500 gigabytes of memory. In reality, only expect to have 465~475 gigabytes. They never give as much as they say.

A hard drives RPM speed is also very important. Hard drives have platters inside that rotate at fast speeds. The faster it rotates, the faster you will load and save things. Some standard RPM speeds are 5400, 7200, 10000 and 15000. 5400 is what you find in a lot of cheaper laptops. 7200 is the standard speed in desktop computers. 10000 and 15000 are very fast speeds that many enthusiast enjoy but they can get kind of pricey.

The example then says that it is SATA 3.0Gb/s. This is the port used to plug the hard drive into the motherboard. The most current version of SATA runs at 6.0Gb/s. 6.0 isn't needed as much for regular hard drives as it is for solid state drives. These are talked about in this article.

The cache for this hard drive is listed at 64MB. Cache is RAM specifically made for the hard drive but cache is faster then regular RAM! Because it is built into the hard drive it has less latency and runs much quicker. I try to find hard drives with 64MB of cache but 32MB is okay also.

Things to Keep in Mind
These are the most important things to know but before making the purchase, check the benchmarks previous buyers have posted in reviews. Check how many MB/s the hard drive runs at. Lots of times hard drives run around 70~130 MB/s. Don't settle for anything too low.

Although companies like Western Digital and Seagate have a good reputation for making hard drives, remember that even these companies can make lemons. Always search for hard drives based by user reviews after narrowing your search. After reading these reviews, you will know what to expect for pros and cons.