All of this discussion begs the question, “What PSU do I currently have?“. Whether you believe in the philosophy of pre-builts / OEMs or have built your PC by yourself from the ground up, finding what PSU you use is as simple as looking at the supply itself, for the most part. After this guide, you too will know what power supply you have.
What is a Power Supply?
Put simply, the PSU of your computer converts AC Power from the mains into DC Power. While doing so, it also steps down the voltage from say 220V to +12V, +5V, and +3.3V DC to power your PC’s crucial components. You can probably understand how even a slight hitch in power delivery can literally set your PC on fire. Unlike the CPU, motherboard, GPU, and whatnot, your PSU is not a smart device. Therefore, no amount of software can ever determine your current PSU, unless, if you have an OEM-specific application but that’s the exception rather than the rule. READ MORE: PC Power Supply Buying Guide – How to Choose The PSU For Your Gaming PC ➜
How Do You Know Your Power Supply Model?
In almost every case, you’ll have to physically inspect your system to see what PSU you have. Let’s go over this step by step.
1) Pre-Builts and Gaming PCs
2) OEM Systems
A quick word of advice, we strongly suggest users swap their OEM PSU for a more reliable and well-known brand for performance and safety reasons. While OEM PSUs can be decent or even good at times, there is no sure way of knowing unless someone has extensively tested that unit, the chances of which are low to none. Anyhow, if you still want to know the maximum power output or detailed specifications of your OEM PSU, there are a few methods.
3) Check the Purchase Receipts
If you still have the receipt of the purchase of your PC, then you can consult that to go over all the components; including the PSU. Even if you don’t have the physical copy, try going over your old messages with the seller since most online vendors also send you a soft copy as well. In addition to knowing your PSU model, you can gain insight into other parts of your PC as well with this method.
4) Use Software to Check Your PSU Model
Remember when we said that the PSU is a “dumb” component? That is still technically true as all your PSU does is supply power and regulate it. There needs to be some data connections between the PSU and motherboard, for which we currently do not have an industry-wide standard. Some brands do offer a feature in higher-end PSUs and motherboards that allow users to monitor their PSUs using software. An example is Corsair’s iCUE software that can monitor PSUs (Corsair AXi, HXi, and RMi series). Since this feature serves a small niche of the entire market, most brands don’t bother adding software monitoring options for PSUs. So if you want to know your PSU using software, you’re basically at the mercy of your brand at this point. READ MORE: The 5 Best Entry-Level Budget PSUs For Gaming PCs ➜
How to Pick a Good PSU?
Never cheap out on your Power Supply! Your PSU can make or break your PC. Those $20 you just saved could cost you your entire system in the worst-case scenario. Good PSUs sacrifice themselves before any damage occurs to the system. So, in light of this argument, what exactly qualifies as a good Power Supply?
1. How Much Power Do You Need?
The first step is to determine your needs. You may use online tools such as Newegg’s Power Supply Calculator to see how much power your system may require at full load. Assume you are pairing an RTX 3060 (TDP: 200W) with a Ryzen 5 7500F (TDP: 65W), this puts us at 300–350W, considering additional headroom for other components. Despite this, many (including the online PSU Calculator) will suggest a 500–600W PSU, to be in the safe zone.
2. Choosing the Appropriate PSU
Once you have decided on the required wattage, it’s time to pick the Power Supply of your choice. Word of advice, don’t blindly trust all numbers you see by manufacturers. We strongly recommend users go over independent reviews consult the PSU Cultist tier list and make sure your PSU isn’t below Tier C (Low-end).
↪ Single vs Multi Rail PSUs
On a PSU, you’ll typically see 3 rails; +5V, +3.3V, and +12V. These serve different purposes; A while back, PSUs used to come with single or multiple +12V rails. The +12V rails carry the most power, so, for safety reasons, they were split up into multiple channels. In the case of MSI’s MPG A850GF, you’d expect that the +12V rail can deliver 850W in all conditions, but that’s partially true, as in the given example, the +12VVGA1 (1st GPU) can only be supplied with 480W of power (12V x 40A). As you can see, the XPG Pylon 650 can deliver 648W from the single +12V rail (12V x 54A), ample for most budget CPU+GPU combinations. Therefore, while rare, it is still important to check whether the PSU you’re choosing has a single-rail or a multi-rail setup.
↪ Output Wattage and Efficiency
The “Total Continuous Power” figure is a combination of total power drawn across all the stated power rails at any given moment. The “Output Wattage” on the contrary is the theoretical maximum of what each power rail can deliver. All these rails cannot achieve their peak output wattage concurrently and will add up to the Total Continuous Power. Moreover, efficiency is more important than you think! If your PSU is 80% efficient (80 PLUS) and uses 500W at any given moment, then 625W will be drawn from the wall due to efficiency losses. At 94% efficiency (80 PLUS Platinum at 50% load), this would reduce to 532W. These values are measured from 20% load to 100% load. Your efficiency could drop if your system uses <20% of the total PSU’s capacity. In any case, 50% load seems to be the sweet spot for efficiency. In a theoretical system that has a 2000W PSU and the total load is at 50% (1000W), here’s the difference you’d see between an 80 PLUS PSU and an 80 PLUS TITANIUM PSU:
80 PLUS: 1250W From the Wall80 PLUS TITANIUM: 1063W From the Wall
That’s a near 200W difference. If the system is run 24/7 for 30 days, then you’d see a 144 unit (kWh) energy consumption difference between the two. Electricity rates in California are around 19.90 cents per kWh, so you’re looking at $30 savings per month. READ MORE: The Difference: Gold vs Bronze Rated Power Supplies ➜
Conclusion
Long story short, if you want to know what PSU your system uses, just remove the side panel and look at the PSU sticker. If there is no sticker present, however, you could search online for your OEM system (OptiPlex, ThinkCentre, etc.) and try to match the exact model. There are many reasons why you’d want to know your PSU’s details. If you’re looking to get a new GPU, many old supplies simply lack a 1×8 pin or a 1×6+2 pin connector. You do want to look out for motherboards in OEM builds that lack a 24-pin connector. In that case, if you wish to replace the PSU, you might have to swap the motherboard as well.
