I'm building my first computer and have a question regarding Hard Drive Interface Speeds. One of my friends told me the speed of a hard drive is important and that a slow hard drive will basically slow down your entire computer. Is this true? If so, what is a recommended are drive speed and what storage size do you recommend (I am going to use it for gaming) also what hardware is needed to connect your hard drive to your mobo and what are reliable brands you've had experience with.
Yes, hard drive speeds are important. With modern processors as fast as they are, every time you're waiting for your PC to do something chances are it's the hard drive that's holding things up.
It's important to understand that there are two different ways to measure drive speed: access time (how long it takes to find a file), and transfer rate (how long it takes to read or write the file once it's been found). For most people who want the computer to boot and start programs up quickly the access time is the most important factor. This is because there are a lot of files that have to be found, but they're not terribly large.
There are basically three classes of disks: "Green" drives which use low power, typically spin at 5400rpm, and have relatively slower access times and transfer rates (most laptop drives fit in this category too). Standard drives spin at 7200rpm and have medium speeds. And high-performance drives spin at 10,000rpm or more and have the fastest access times (although these drives typically don't have transfer rates any better than the other drives).
SSDs (Solid State Disks) are the ultimate in performance - they have access times that are about 100X faster than a standard hard drive. But they are expensive and have limited capacity.
The best combination is usually to buy as high-performance a drive as you can afford, even if it's relatively small, and use it to install the operating system on. Then you can buy a larger, slower drive to hold all your data files. Generally speaking, it's a lot less critical to have good performance for your data (but there are exceptions - video editing is one that comes to mind).
Somewhere in the range of 60 to 120GB or more is probably a good size for the OS disk, depending on how much stuff you expect to install on it. For the data disk, the sweet spot in terms of cost/byte seems to be around the 1TB size.
All modern desktop drives and motherboards use a SATA connection, it's pretty foolproof. But if your motherboard is older than a 2-3 years it's possible you need IDE (also called "PATA") drives.
Modern drives and motherboards use SATA Version 2.0 which has transfer rates of about 300MByte/sec. This is faster than needed for any hard drive and it's even fast enough for pretty much all of the SSDs on the market right now. SATA Version 3.0 is just starting to be rolled out in the newest products, and it might be required to get the best performance out of SSDs which will be introduced in the coming years.
Just a note of caution. Many gamers in the past have sworn that you get the ultimate performance by using a RIAD0 array system of 2 disks, preferably using the very fastest Raptor disks or something like that. I am NOT a gamer, so don't consider my advice the best in your field. BUT if you want to consider the RAID0 route, look up the info carefully. RAID0 has risks involved, more that a "normal" disk system, that make it extra important to have a good regular and frequent backup system in case you lose ALL your data. Plus, I have the impression that most modern HDD units are so fast that the advantages of RAID0 are small (but still not none), so you have to weigh advantage versus cost versus reliability.