(Jan. 06, 2007): Power Guide Revision 1.2.2 [slight sentence modifications]
This post is about the stuff that runs your computer and some of the tools you can use to protect your investment. Though I will be talking from a North American perspective in this guide, the same basic rules apply worldwide. A good knowledge of power systems will help you not only protect the considerable time and monetary investments you have in your computer, they will help you create more stable voltages to enjoy overclocking with. For those of you who also know your stuff, please don't post things about how I oversimplified a few things... it's just a basic guide.
This post is divided into a few sections:
- Chapter 1: Electricity Basics (covering AC/DC function, what line noise is, and how it affects you)
- Chapter 2: Protection Devices (covering the differences between various devices)
- Chapter 3: How Much Difference Does It Really Make? (a quick and rough look at how some general products can make a difference)
- Chapter 4: What Products/Brands "The Power And You" Sticky Guy Recommends (Coming Soon!)
Chapter 1: The Basics
Let's start simple. The electric current that runs your household appliances and tools is called AC or Alternating Current power. Your computer and other electronic devices however, run on DC or Direct Current power. The difference is that AC power reverses the direction of flow constantly, ideally averaging 60 cycles / second here in North America, whereas DC power flows in only one direction. With me so far? To convert from AC to DC power your computer requires its power supply. Without going into the gory details, just know that it converts your power directly as it receives it, which is why surges in your power line will often result in a dead computer (especially an already overclocked one).
Now to go a little deeper... In North America we are on the 120 volts system, which means that voltage supplied to our electronic devices at wall outlets should be a perky 120 volts. Unfortunately for us, this is not very often the case for more than a few milliseconds. Believe it or not, the actual codified tolerance range is 105-130 volts... meaning you could be down 15 volts (over 10% of your ideal) or over by 10 and your power company won't care in the least. Now just try to imagine whether or not you would mind your 3.3V rail registering at 2.9V instead, or your 12V operating at 10.5V. You wouldn't like that much, would you? These fluctuations occur for a variety of reasons, but the most easily grasped concept is that everyone on your power grid who turns on an electrical device draws some little bit away from the main line, which give very slight drops in electrical current. These drops turn into the most common power issue: sags. To give you some context, a larger example of a sag is a brownout, which occurs when there is just too much load on the grid.
These constant miniscule sags do add up, the amount depending on your location, time of day, and current weather conditions. These small sags, in addition to the small surges which also frequently occur, are collectively called 'noise' . This 'noise' is further increased by things such as attenuation of the electrical line as it goes to your home, and by other devices in your own house.
Obviously, this noise in your AC line translates directly into noise on your DC computer line. The amount of translation can vary by the quality of your power supply, but even the best power supplies are no match for even mid-grade solutions when it comes to getting rid of this for one very important reason: feedback . Feedback is noise generated by your electronic devices themselves that returns to your power supplies and home lines, then is regurgitated back to your devices themselves. You can think of it as localized line noise.
Now that you've gone through all that, I think you are ready for us to go over some of the devices you can use to combat these problems.
Chapter 2: Protection Devices
Surge Protectors
Probably the most misunderstood of all the devices listed, a surge protector is basically what its name implies. A funny and little known fact about surge proctors is that after an average lifespan of 1.5 years, they die. But please, before you post a reply about your power bar having lasted 10 years, read on. Most power bars are purchased for $10 or less at a Wal-Mart or equal quality store. These power bars however have a dark and dangerous secret: they trip out and DO NOT TELL YOU. A slightly better quality one comes with an LED indicator usually under the on/off switch, which will alert you when it has been tripped. It often does so by blinking repeatedly. It will still function as a multiple-outlet bar, but will not continue to provide any protection. Finally, the highest quality surge protectors will feature a 'reset' button which allows them to continue to provide functionality after a surge.
Cost: $5-$30
Line Conditioners
A clear step up from the surge protector is the line conditioner. They generally have all the same features as surge protectors, but with one important enhancement: they have at _least_ one filter on them to eliminate line noise. Doing this ensures you get a much smoother electric flow and lets your power supply do its job with less stress and significantly enhanced reliability. A good line conditioner for general enthusiast computing use would be in the range of $100, though those of you with advanced cooling or bleeding-edge systems may consider upgrading to something up to $200. In my honest opinion, anything much over that is a waste in most home computer applications.
Also worth noting: while line conditioners are great things to have, please don't go overboard. Yes, your computer is amazing with it's many Gigabootz of power... but you don't need to find a line conditioner with a specialized high-current subwoofer outlet for it. High-quality devices with such specialized outputs have special filtering circuitry specifically designed for their respective purposes, and you will find that plugging into such an outlet will not offer a device that does not fit into that niche does not offer any added benefit (it would likely offer less quality than plugging into an outlet made for digital devices).
Cost: $100 - $1800 [depending on joule rating, quality, and features]
Power Regulators
An AC power regulator is basically a large, often overpriced device designed to supply you with a constant voltage amount. While they protect well against surges and even prolonged sags, it should be noted that one must still use a line conditioner in addition, because they do nothing for noise (generally). Though it sounds like a spiffy add-on to your system, I have a very hard time justifying the cost given the almost negligible benefit in contrast to other options at similar price points.
Cost: $300 - $2200 ($1000+ suggested)
UPS - Uninterruptable Power Supplies
Although I could easily devote an entire post to UPS's, we'll just cover the basics here. Basically, these are surge protectors with built-in batteries in case of blackouts. In days gone by these batteries would often not come on fast enough for a computer, but now that switching is so fast that your computer is unaware it ever took place. There are many things to look for in a UPS, the two most important of which are:
1. It's power rating. No use in having a UPS that won't supply enough power to let you do a clean shutdown.
2. Intelligence. UPS's are coming with an increasing amount of 'intelligence'. Now a person can pick up even a relatively cheap model and connect it via USB to their computer. This will allow them to monitor the condition of the battery, current line conditions, and will also let the UPS shut down your computer for you in the event you are away and something happens.
One important thing to remember about a UPS is that the batteries do have to be replaced. How often is dependant on the type of battery and the amount of use it's had (more is actually better, to a point). These replacements are not generally that expensive, usually around the price of a replacement car battery (which is actually what a lot of these use).
Finally though, I would like to make one final point about UPS’s; unless you purchase an 'online' UPS (one that is constantly on and constantly recharging itself) or one which specifically states otherwise, these do NOTHING for line noise at all… and the quality of noise filtering on most lower- to mid-priced models is questionable (if a good line filter costs $100 minimum alone, how is that plus an intelligently managed battery selling for under $80?).
Cost: $30 - $100 000+ (don't cheap out though - expect to pay at least $100)
Chapter 3: How much difference does it really make?
In terms of hurting your computer, you definitely need a surge protector as a minimum. Above that, I leave it to your discretion, but the more you live on the edge the more I suggest in investing. Electrical damage is the #2 reason for computer failure (after hard drives), and can be very hard to trace. As a point of fact, feedback line noise is actually the #1 current reason that plasma televisions die so early... and beating out heat can be a hard thing on something that runs that toasty. Just proof positive that line noise = bad for sensitive electronics.
After going through all that I bet at least some of you are wondering how much getting a line conditioner really helps with line noise, so I thought I would post a few test results. For this test, I compared 3 of my favorite entry-level power line devices: a basic Monster brand power bar, a Monster brand stage-1 line filter, and a Monster brand stage-2 filter. To keep it fair none of these devices have anything else plugged in to them, unless specified. My tool to do this was actually supplied by the Monster cable company, and is basically just a sensitivity device that outputs line noise as decibels on an LCD screen and also gives you an audible representation as well. With dB in this case, lower is better.
Household Appliance Jack:
-> Used to calibrate the line noise display to ~100dB (+/- 8dB), just to get a convenient reference number.*
Monster Power Bar:
- Displays ~100dB (+/- 8dB), the same as any house outlet.*
Monster Stage-1 Line Conditioner:
- Displays a relative line noise of ~14dB (+/- 2dB)
Monster Stage-2 Line Conditioner:
- Displays a relative line noise of ~.1dB (+/- .1dB)
*Note: In the event that these numbers did not help convince someone, I would like to make one last addendum to this guide. That is that with the household jack and the non-filtered power bar, the line noise was so prevalent that I could actually hear a local radio station coming in over the audible output, through the static. It was undetectable on either filtered outlet.
I hope you have found this enlightening. If you have any questions, please post them here and I (or someone else) will be happy to try to answer them for you.
~ Serra
