DESKTOP PC POWER SUPPLY UNITS - PSU

5 Things to know when buying a Power Supply Unit (PSU) for Desktop PC

When you are assembling a new desktop computer, don’t give in to the temptation of buying a cheap power supply unit (PSU). The PSU supplies power to your entire system, and a bad one can cause that expensive motherboard or graphics card to malfunction. Don’t take this risk, ever!

PSUs don’t have the same marketing or glitz value as graphics cards or processors. You know that you want Intel’s new Skylake CPUs and you’ll endlessly debate Nvidia vs. Radeon, but chances are, you’d go with just about any PSU, right? That’s a mistake one that will cost you big time.

That’s not to say that you need an expensive PSU. There are budget models available, which fit the idea that it’s cheaper to build your own PC. But you need to know what to look for. So here’s a quick guide to selecting the right PSU without breaking the bank.

1. Continuous Wattage > Peak Wattage

Wattage is the base number to help you distinguish which PSU you need and how it is rated. Simply put, this is the total amount of watts the PSU can deliver to the different parts of your PC. You’ll find models that provide 300W and some that go all the way up to 1200W.

While models will advertise this number proudly on the box, it might not tell you the full story. For example’s sake, consider a hypothetical 500W PSU. If it means Continuous Wattage, that’s great. If it’s the Peak Wattage, you might want to avoid it. You can usually check which it is on the model’s specifications page.

Continuous Wattage and Peak Wattage are ratings based on tests by the manufacturer. Continuous Wattage indicates that it can deliver those 500W continuously without fluctuations. Peak Wattage indicates 500W is the maximum power it can deliver, but probably only for a minute before dropping down.

In simple buyer terms, look for continuous wattage ratings, ignore peak wattage ratings, and ignore a product that doesn’t advertise its continuous wattage rating. If you can’t tell which one it is, don’t take your chances and just move on.

2. How Many Watts Do You Need?

Not all PCs are built alike, so the amount of power each one needs is different. A high-end gaming PC is obviously going to need more watts to run than a simple home office PC. But how do you calculate the amount you actually need?

The Internet is full of simple calculators that will do the job for you. Try Outervision’s Extreme Power Supply Calculator or Cooler Master’s Power Supply Calculator. If you know what you’re doing, Cooler Master’s version is better, but if you’re not sure about what parts the calculator is asking for, stick to Outervision’s basic calculator.

Both calculators will give you a certain idea of how much wattage you need, and depending on how you entered your information, feel free to round it up to the closest PSU.

In fact, you could even go two rungs higher. For example, if the calculator says you need 370W, then a 400W PSU should be fine but 500W wouldn’t be bad either especially if you plan on adding more parts to the rig eventually.

3. Save Energy With Efficient PSUs

Our social responsibility to the planet compels us to not consume more resources than we need to, so get a PSU that is as efficient as possible! Even if you don’t care about the planet, an efficient PSU will still save you big bucks on your energy bill.

So what is efficiency in a PSU? Well, your PSU is taking AC power from the outlet and converting it to DC power, which is then sent to all the parts but typically the PSU wastes some energy in the conversion process. Therefore, PSU efficiency is about how much it can convert and how little it wastes.

Therefore, an 80% efficiency indicates it’s able to convert 80% of the AC power to DC while 50% efficiency indicates it converts 50% of the AC power to DC. In even simpler terms: a higher efficiency percentage is better and will require less power from the outlet.

The most efficient PSUs are the ones that come with an 80 Plus rating, which is assigned by an independent certifier. Even in 80 Plus PSUs, there are different levels: 80 Plus, 80 Plus Bronze, 80 Plus Silver, 80 Plus Gold, 80 Plus Platinum, 80 Plus Titanium. (These are ordered from worst to best.)

An additional advantage of these efficient PSUs is that they generate far less heat than other PSUs, and usually run at quieter volumes too. Manufacturers will advertise 80 Plus certified PSUs proudly, but in case you’re having trouble finding information, check the full list of 80 Plus PSUs.

4. Details You Can Safely Ignore

Everything up to now has just been about the bare basics of PSUs. As with any technology, you can geek out and get a lot more specific about what you want or need, but if you are a beginner, the aforementioned three aspects will matter the most to you in your buying decision.

That being said, there’s some other jargon you might encounter while shopping for a PSU. You can safely ignore all of this until you’re more familiar with PSUs in general, but if you’re curious about what they mean, here are some specs you might see.

  • Rails: You can get multi-rail or single-rail PSUs. Both have their pros and cons and you don’t need to worry about the technicalities right now. If you live in an area where power fluctuations or outages are normal, then you should consider multi-rail. For any other scenario, or if you use a good uninterruptible power supply (UPS), then just get a single-rail PSU.
  • Voltage Stability: If you’re ticking all of the above boxes, then voltage stability won’t be an issue. This basically refers to the PSU’s ability to keep supplying power at 12V without dropping.
  • Cabling or Connectors: Unless you’re buying a high-end specialized PSU, you should be fine with the cabling that comes in the box. High-end PSUs do offer something called “modular cabling”, which lets you fit custom cables and pin connectors to attach your parts to it. Not important for the average user.
  • AT vs. ATX: Some PSUs are made for AT-type motherboards, others for ATX-type, and some for both. Chances are, you’re using a standard ATX motherboard and will need a standard ATX PSU, but you may want to double check your motherboard’s details just in case.
  • Repair Units and Accessories: No, you don’t need a wattage tester or guides on how to fix a PSU. If you diagnose a problem with the PSU, your only option is to replace it and hope that it’s still under warranty.

5. Why You Shouldn’t Cheap Out

So why are we harping on about buying a quality PSU instead of just going with whatever came bundled with your PC case or a relatively unknown brand’s models? Well, like we said at the start, your PSU affects every part in your computer system and can end up frying circuits in the case of a power fluctuation.

But apart from that, quality PSUs have other benefits that make them worthwhile. Here are a few:

  1. They last a long time. No, really. Chances are that if you buy a quality PSU right now, rated about 100W to 200W higher than what you currently need, then you’ll be able to use it for your next PC upgrade as well. At the very least, it’ll last you several years.
  2. They have resale value! Upgrading to a new PSU? You’ll find buyers for your old one on Craigslist and Ebay. Heck, you could even repurpose it as a bench power supply for DIY projects.
  3. Standardized sizes let you get creative with old PSUs too. Since all PSUs are generally shaped the same, just find a simple case and you can make yourself a cool and quiet HTPC.

What to Look For When Getting a Power Bank

With the development of science and technology, our devices, phones, tablets, cameras etc. become more and more an integral part of our life. They are not just part of a lifestyle they have become markers in our personality.

Imagine being on the move, and your phone battery drains out. Anyone who has witnessed such knows how demoralizing it feels being separated from your device. This has made having a reserve source of power a necessity. But with the amount and variety of power banks in the market, to look for power banks that fit you is a massive undertaking.

Here are a few pointers before you acquire a power bank.

1. Power Bank’s Physical size

I feel this is one of the first things to look out for. I once had a power bank that was three times the size of my phone (an iPhone 5) and weighed just as much as it looked. The obvious problem I had was how to fit it in my pocket. So many times I had to leave the phone in my pocket and carry my power bank in my hand. It did not feel like the ideal way to manage my device.

That said, if you often move around with a purse, the size may be less of a concern for you, but you should also know that the physical size in most cases may not have anything to do with the capacity or strength of a power bank.

2. Number of charging ports

Obviously, the number of ports determine how many devices can charge at the same time. Basically, the more ports there are, the more devices it can charge simultaneously. Interestingly, this factor sometimes has an effect on the size. So if you want a power bank that fits seamlessly in your pocket, you may be looking for one with only one or two ports.

With the increasing amount of portable devices that range from MP3 devices, Bluetooth devices, phones, tablets, and iPads, it is sometimes more efficient to acquire a bower bank with many ports so that no matter what your needs are, you are sure to have all your devices accounted for.

3. Voltage for Power Banks

When looking for a power bank, consider the voltage of utmost importance because, unlike other factors, this might pose a safety risk. The rule is quite straightforward: don’t buy a power bank with a voltage higher than your battery. So, for instance, a 5.5 V power bank for a 3.7 V battery may not be the best choice.

This is because if you charge your battery with a power bank that has higher voltage, it begins to swell and may even explode. Also, if you charge your battery with a power bank of lower voltage, it may never charge.

4. Capacity

The capacity measured in milliamp-hour, or “mAh,” is a key factor to knowing how much power it will use to charge your device and how often you will need to charge it.

Common capacity ratings are 2,000mAh to 15,000mAh, and in some cases as high as 40,000mAh. The higher the power, the more the times it can charge your device. While you look for power bank, you should consider how many devices you have and invariably the amount of capacity that might be required to fully charge your devices.

5. Average Power Bank Prices

This is almost always the factor that determines which of the other factors will be accommodated. With prices from R56,75 all the way up to R1418,86, you are likely to find something within your budget. I will usually recommend one towards the upper end of your budget because cheaper may not always be better, and often what you pay for is what you get.