The Right Tool For the Job
The first thing that's important to understand is that just like any specialized task, it's of utmost importance to have the right tool for the job. When it comes to working with real-time audio on a computer, your average off the shelf PC is often not well suited to this particular job. It's for this very reason that there are actually a number of companies that sell purpose-built PC's which are designed and tested to meet the particular requirements of audio and video work. These companies build Audio Workstation PCs that are certified and tested for doing audio production and recording:
http://www.sweetwater.com/creation_station/
http://pcaudiolabs.com/
http://www.adkproaudio.com/
It's also important to understand that it's never just a matter of processing power, memory capacity, or hard disk speed. These factors are certainly important, but you need not only a capable system, but also a system where all the parts and components work well together. Your average off the shelf computer from a local retailer may be inexpensive, and even packed full of features and powerful, but if the different components comprising this system don't work well together or even interfere with each other, you may end up with a system that by it's very nature just can't deal with real-time audio effectively, and you end up with drop-outs in your recordings, loss of connection, or any number of other problems.
Even a top dollar machine with all the bells and whistles can fail miserably when it comes to working with real-time audio. For instance, PC's spec'd and designed for Gaming are usually real powerhouses in terms of system specifications, but very often the requirements and optimizations for the latest and greatest gaming system (graphics and processor intensive tasks) can be at odds with what an audio workstation needs, and the same video cards and graphics drivers that give you blazingly fast 3D graphics can cause major problems with such time-sensitive operations as real-time audio.
Real-time Audio and Operating Systems
Another thing to consider is that Windows PC's often require a fair bit of research and optimization when it comes to working with audio. We have our own knowledge base article on optimizing your computer for audio production:
Optimizing Windows Vista and Windows 7 for Music Production
You'll also find numerous similar guides from other manufacturers and websites as well:
Avid, maker of Pro Tools
Steinberg, maker of Cubase and Nuendo
Native Instruments Optimization Guide
Focusrite Optimization Guide
Prism Sound Optimization Guide
Sweetwater Windows 7 Optimization Tips
Optimization Guide from createdigitalmusic.com
Here is a two part article on getting a computer for Audio production you may find useful as well:
Lifting the Lid on Audio Laptops - Part 1 and Part 2
There is also a company called Resplendence that actually makes a very useful tool for troubleshooting issues with PC hardware and drivers causing problems with real-time audio:
http://www.resplendence.com/latencymon
To quote directly from the Latency Mon site:
"Windows is not a real-time operating system. All requests to the operating system are delivered on a best effort basis. There are no guarantees whatsoever that requests are delivered within a certain time frame, which are the characteristics of a real-time operating system. That is not a problem for most devices and tasks but this is bad news for audio applications (which are considered soft real-time) because they need to deliver data to the subsystem and the hardware in buffers several times per second. If one or more buffers miss their deadlines and are not delivered in time it has audible consequences which are recognized as dropouts, clicks and pops. "
The bottom line is, while you can certainly use a Windows PC as an audio workstation, there's no guarantee that just any PC will be the right tool for what amounts to a very specialized job.
Firewire Connection Considerations
Another consideration is the audio interface you use and the method of connection to your computer. In the case of a firewire audio interface, you will need to have an actual firewire connection. You may be able to find Firewire to USB adapters, and they may work for connecting external hard drives or cameras and other peripherals, but generally speaking, they will not work for audio interfaces.
If your computer does not have a firewire connection built in (or often times even if it does), you will need to find an expansion card that will enable you to add a firewire connection to your computer.
The most important consideration is the firewire chipset of your firewire connection. You'll find that this is generally a requirement of any manufacturer of any firewire interface. Different firewire chipsets handle data differently, and some are better suited to the requirements of streaming multi-channel real-time audio.
Most Macs come with a built in firewire connection that has a compatible chipset, or if it's a newer Mac without firewire but it has Thunderbolt ports, you can use the Apple Thunderbolt to firewire adapter, which also uses a compatible chipset and functions essentially the same as an add-in firewire card.
You can find Windows PC's with built in firewire, but they usually use firewire chipset that's unsupported, so normally you'll need to get an add-in firewire card of some sort that does use a compatible firewire chipset.
Here is a link to our hardware compatibility document to use as a guide: Approved Firewire Cards
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