Generally, more complex systems require more power to run. A desktop with a custom liquid cooling loop, a high-end motherboard, and dual GPUs is going to need a higher wattage computer power supply than a simpler system.
Consider EfficiencyWattage is certainly an important consideration when choosing a desktop power supply, but so is PSU efficiency. Inefficient delivery leads to wasted power and more heat, which can potentially decrease the lifespan of your components.
Some power supply manufacturers will build in protections to help keep your components safe from power-related issues. These protections often add some cost to a power supply, but they can offer some additional peace of mind as well.
The first is overvoltage protection, which refers to a circuit or mechanism that shuts down the power supply unit if the output voltage exceeds the specified voltage limit, which is often higher than the rated output voltage. This protection is important since high output voltages may cause damage to computer components that connect to the power supply.
The second is overload and overcurrent protection. These are circuits that protect the power supply unit and the computer by shutting down the power supply unit when there is excessive current or power load detected, including short circuit currents.
Although there are still AT form factor power supplies available for purchase, AT form factor power supplies are undoubtedly legacy products, on the way out. Even the later ATX form factor power supplies (ATX 2.03 and earlier versions) are falling out of favor. The major differences between the ATX and AT power supply form factors are:
The ATX12V form factor is the mainstream choice now. There are several different versions of the ATX12V form factor, and they can be very different from one another. The ATX12V v1.0 specification added over the original ATX form factor a 4-pin +12V connector to deliver power exclusively to the processor, and a 6-pin auxiliary power connector providing the +3.3V and +5V voltages. The ensuing ATX12V v1.3 specification added on top the 15-pin SATA power connector on top of all that.
A substantial change occurred in the ATX12V v2.0 specification, which changed the main power connector from a 20-pin to a 24-pin format, removing the 6-pin auxiliary power connector. Also, the ATX12V v2.0 specification also isolated the current limit on the 4-pin processor power connector for the 12V2 rail (+12V current is split into the 12V1 and 12V2 rails). Later, the ATX12V v2.1 and v2.2 specifications also increased efficiency requirements and mandated various other improvements.
The Small Form Factor (SFF) designation is used to describe a number of smaller power supplies, such as the SFX12V (SFX stands for Small Form Factor), CFX12V (CFX stands for Compact Form Factor), LFX12V (LFX stands for Low Profile Form Factor) and TFX12V (TFX stands for Thin Form Factor). They are all smaller than the standard ATX12V form factor power supply in terms of physical size, and small form factor power supplies need to be installed in corresponding small form factor computer cases.
Next up is the processor power connector, which comes in 4-pin and 8-pin versions. As with the main power connector, many modern motherboards have switched to the larger format. Again, make sure your power supply is compatible.
A Power Supply Unit (PSU) may not be as exciting or glamorous as a brand new graphics card, but that doesn't mean you can skimp out on it. Your power supply is the beating heart of your PC's components, and if you buy a cheap one, it threatens to take out your entire computer!
While models will advertise this number proudly on the box, it might not tell you the full story. Let's say you see a 500W power supply. If it states 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.
Not all PCs are built alike, so the amount of power each one needs is different. A high-end gaming PC will need more watts to run than a simple home office PC. This is because powerful processors and graphics cards require more power to run.
If you purchase an underpowered PSU, your PC will lose power during intense processes. But how do you calculate the amount you actually need Fortunately, the internet is full of resources you can use to calculate your computer's power needs.
Therefore, an 80 percent efficiency indicates it can convert 80 percent of the AC power to DC. Similarly, 50 percent efficiency indicates it converts 50 percent 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 JonnyGuru Forums are packed with reviews and feedback on power supply units and are well worth searching for your PSU make and model. You can also head over to /r/buildapc on Reddit to find out which PSUs people are leaning towards, not forgetting our own roundup of the best PSUs for PC builders.
A common issue people come across when building a PC is working out just how much power they'll need. Power supply units are sold based on the wattage they can supply. The more components you're using, the more power you'll need to power your system.
So you might simply think that buying the biggest PSU is your best course of action, but that's not always the case as it's wasteful, both in terms of money spent and power used. Plus it might also cause problems with the case you've chosen.
On the other hand, it might also be tempting to save money by purchasing a cheaper PSU. Skimping can be an issue too as a poor-quality power supply can potentially short out, surge or simply destroy your entire PC.
You might see that Mini-ITX, Micro-ATX and even some mid-tower ATX cases need a smaller PSU. It's important to check the specs of your case before you buy it or the PSU you'll need to power your computer to make sure they both work comfortably with each other.
Some smaller cases need an SFX PSU as these are smaller and don't take up as much space, but yet are able to deliver enough punch for your system. It's worth noting though that you can't often get high wattage power supply unit in the small form factor design. So don't expect to cram a high-end gaming system inside a tiny case.
Equally, the larger 1,000-watt and upward power supply units are often larger in size and might not fit all cases. Even some mid-tower cases might struggle with some of the bigger power supplies. So it's important to check the specs of your preferred case before you commit to the various parts.
The good news is though, for the most part, you don't need to worry if you're buying the latest graphics cards from Nvidia. Older power supplies will still work with the RTX 40-series GPUs assuming they have enough wattage to hit the recommendations.
The reason for this is Nvidia is adopting the new PCIe 5.0 power connector (12VHPWR) on its GPUs. In future, this will mean that you can purchase an ATX 3.0 power supply. That will have a dedicated PCIe Gen 5 connection, so you can get a single cable to connect from the PSU to the GPU.
Adrian has been a tech enthusiast since the 90s with a particular passion for gaming that developed thanks to his first gaming outings on Pong, Zork and Space Invaders.In the years that followed he dabbled in various games consoles and personal computers starting with the humble Commodore 64 before moving to Sega Mega Drive, Dreamcast, Nintendo 64, PlayStation 2 and then into the world of PC gaming. His gaming outings online in the days of dial-up modems included Command and Conquer and Battlefield 2 before he found the joys of gaming communities and started Enemy Boat Spotted over 10 years ago.Over the years, Adrian's passion for technology has grown. He has built multiple gaming PCs by hand, and equipped his home with a variety of smart devices. He has been writing about tech and gadgets for the last few years and enjoys sharing that passion with anyone that will listen.Adrian is currently obsessed with Virtual Reality and is excited to see the future that holds for all of us.
You don't need a degree in rocket science to work out the wattage requirements for your system. The recommended system power requirement listed on the specs list for your current or future graphics card is a great place to start. Still, we recommend using an online power calculator to get the most accurate figure. OuterVision's Power Supply Calculator is our go-to.
Once you've found out the wattage you'll need for your PC, you'll need to decide what efficiency you can afford. Power supply manufacturers all tend to agree to the same PSU efficiency rating system: 80 Plus.
Reliability, customer support, warranty, and manufacturer reputations are among the first things you should look for when choosing the best power supplies. Since there isn't exactly a single solution that makes sense for every build, we decided on several categories to fit the needs of most PC gamers. For each, we also took into account budgets, compatibility, unique features, and design.
As a word of warning, compatibility is a significant factor when it comes to power supply units. Using cables from different PSUs could put your entire PC at risk, so stick with those provided. Even if they are from the same manufacturer, not all PSU cables will be universally compatible either, complicating things further. If you absolutely must splinter from the cables included, have a look at your PSU's PIN connectors and make sure your cable set has ones that match to avoid any unnecessary frustration and breakages.
The best power supply (PSU) fuels your PC with the energy it needs to run your components. It's a simple part of your rig, but a crucial one that could become a real pain. The best PSUs need to keep up with power-hungry graphics cards and CPUs and they need to do it with a good level of efficiency. A good PSU should take care of all that work for you, and that's why it's important to find the best there is. 59ce067264