Power supply buying guide: actual wattage, efficiency, and essential protections

The PC power supply is that component that, although it doesn't make the headlines, absolutely supports everything else. Choosing the right one makes all the difference between a stable team that performs at its best and one that freezes, loses performance, or, in the worst case, suffers serious damage from a power surge or spike.

The tricky part is that many variables come into play: power, 12V amperage, efficiency, connectors, ATX 3.x standard, internal quality, and protections. In this practical and comprehensive guide You'll find out how to determine the actual wattage you need, which certifications really matter, what cabling to expect in 2025, and a recommended power map for each GPU (AMD, NVIDIA, and Intel) to ensure you don't fall short. Let's get started. buying guide for power supplies.

How a modern ATX power supply works

A PSU converts the alternating current from the wall outlet into several direct current lines (12V, 5V and 3,3V) with stable voltages and low electrical noise. That energy journey It is not trivial: it generates heat and requires well-designed conversion stages to respond to peaks and instantaneous load variations.

• Reception from the AC power of the grid.
• Transform of the input voltage to the range that will then be rectified/regulated.
• Rectification (half wave/full wave/bridge) to convert from alternating current to direct current.
• Filtered out to soften the curl after straightening.
• Regulatory fine that keeps voltages within tolerances under dynamic load.
• Delivery to each rail and connector according to system demand.

The actual load varies all the time: a GPU with a 200W TGP might be in 50W desktopIt can handle sustained power up to 200W during gameplay and experience brief spikes above that figure. It's vital that the power supply can withstand these transients without instability or drops.

Efficiency and certifications: 80 Plus and Cybenetics

The more efficient the PSU, the less energy is wasted as heat to deliver the same useful power. The 80 Plus label It is the popular benchmark for measuring efficiency at various load points, and it usually correlates with better quality.

• 80 Plus White: ~85% efficiency (best scenario close to 50% load).
• 80 Plus Bronze: ~88%.
• 80 Plus Silver: ~90%.
• 80 Plus Gold: ~92%.
• 80 Plus Platinum: ~94%.
• 80 PlusTitanium: ~96%.

Note: efficiency changes with the loadMany units have peak efficiency between 40–60% of their rated power, and below 10% it can drop significantly. That's why proper sizing is so important.

In addition to 80 Plus, there is CyberneticsIt evaluates efficiency (ETA) and noise (LAMBDA) at many more load points using modern methodology. It provides a more accurate picture of real-world performance and acoustic profile, useful if you're looking for quiet without surprises.

ATX 3.0 and ATX 3.1: PCIe 5.0, 12VHPWR and 12V-2×6

The latest generations of GPUs have brought demanding power peaks and a new connector. ATX 3.0/3.1 It introduces requirements for handling transients and the 16-pin 12VHPWR connector.

The 12V-2×6 standard (evolution of the 12VHPWR) improves security By shortening the detection pins and lengthening the ground/power pins, you ensure the connector is properly inserted before allowing high loads. This is what you should look for in quality power supplies and cables for PCIe 5.0/5.1 cards.

They were documented overheating incidents Initially, problems with 12VHPWR are usually due to improper insertion or aggressive bending. The recommended practice is to connect the cable only after hearing/feeling a click, avoid bending the cable immediately after exiting the connector, and use the PSU's original cables/cables whenever possible.

Wiring and connectors you should demand

A suitable PSU is not just about power: it must bring the correct and sufficient connectors without resorting to makeshift solutions.

• ATX 24 pins for the motherboard.
• EPS/CPU 8 pins (often 4+4); some high-end boards require 8+8.
• PCIe 6/8 pin (6+2) for GPU: 6 pins up to ~75 W, 8 pins up to ~150 W.
• 12V-2×6 (16 pin) For modern GPUs: up to 600W (there are cables limited to 300/450W in lower wattage power supplies).
• SATA and Molex for storage and peripherals.

At AMD, the Current Radeon cards typically use 8 pins. Standard; NVIDIA RTX 30/40/50 series cards with 16-pin connectors include adapters, but a native ATX 3.x power supply with 12V-2x6 is preferable. The more complete the cable set, the better the future compatibility and the fewer headaches you'll have.

Modular, semi-modular or non-modular; and form factors

Modularity doesn't change performance, but it does change the assembly experience and airflow. A fully modular source It allows you to use only what you need, leaving the interior clear.

The semi-modular They leave the essential cables (24-pin and CPU) permanently connected, and the rest are plug-in. non-modular They're cheaper, but they complicate cable management and aesthetics. Consider the small extra cost for a modular system: it's usually worth it.

In terms of size, ATX rules. standard towersFor compact equipment, look for SFX or SFX-LCheck the length of the power supply (e.g., 140–180 mm in ATX) and clearances with GPUs, radiators, and bays.

How to size power: a practical method

The goal is for the power source to work smoothly and with room for peaks. Practical rule: sum CPU (peak), GPU (peak), add 80–150 W for the rest (motherboard/RAM/SSD/fans), and apply an extra 15–30% margin for transients and future upgrades.

PSUs perform best above 50–70% load. If your equipment has a peak power of around 600WAn 850W Gold is a very sensible choice: it withstands peaks, improves efficiency, and reduces noise.

Real cases show that transient spikes can knock down A 650W power supply with a mid-to-high-end GPU, when the recommendation is 750–850W, is causing random shutdowns. Increasing the power supply capacity and headroom eliminates the shutdowns and reduces wasted heat.

Essential electrical protections

Good PSUs integrate an electronic security shield that can save your PC. Demand at least:

• OCP (Over Current): current limit per rail to prevent damage.
• OVP (Over Voltage): cuts off if the voltage spikes above safe levels.
• UVP (Under Voltage): prevents instability from dangerous falls.
• SCP (Short Circuit): immediate reaction to short circuits.
• OTP (Over Temperature): turns off if the temperature gets too high.
• OPP (Over Power): cuts off if the nominal power is greatly exceeded.

ATX 3.1 tightens requirements for transients and response. Be wary of cheap sources They claim "complete protection" without providing actual controllers: sometimes there's only a basic fuse. In Europe, ErP/CE regulations set minimum efficiency/power factor requirements, but this doesn't replace thorough quality verification.

Internal quality, silence and guarantee

The details matter: Japanese capacitors A 105°C operating temperature, high-quality MOSFETs and transformers, a robust PCB, and a good topology ensure long-term reliability. They offer improved stability and lifespan compared to cheaper units.

For the noise, look for 120–140 mm FDB fansHybrid modes (fan off at low load) and finely tuned curves. A well-sized Gold/Platinum will be cool and quiet most of the time.

La Warranty It is a reliable indicator: 7–12 years in mid-to-high ranges is common among reputable manufacturers.

Brands and OEMs to keep on your radar

In the market there are "label" brands and actual manufacturers (OEM). Among reputable OEMs These include Seasonic, Delta, Enermax, CWT, FSP, and High Power. Among the consumer brands with a good track record are Corsair, be quiet!, EVGA, Seasonic, MSI, and Cooler Master, among others.

Avoid bargains of dubious origin, poor packaging, scant technical information, or inconsistent specifications between watts and amps. A very lightweight font Sometimes it reveals savings in transformers/inductors and filtering.

GPU power recommendation (quick reference)

Minimum indicative values ​​for standard configurations (If you use very power-hungry CPUs, go up one step.) Include the type and number of connectors.

AMD Radeon (GCN)

• Radeon VII: 750 W (2×8 pins)
• RX Vega 64: 750 W (2×8)
• RX Vega 56: 600 W (2×8)
• R9 Fury X: 600 W (2×8)
• R9 Fury: 600 W (2×8)
• R9 Nano: 550 W (1×8)
• R9 390X: 550 W (1×6 + 1×8)
• R9 390: 550 W (1×6 + 1×8)
• RX 590: 500 W (1×8)
• RX 580: 500 W (1×8)
• RX 570: 450 W (1×6)
• RX 480: 500 W (1×8)
• RX 470: 450 W (1×6)
• RX 560: 350 W (1×6)
• RX 550: 300 W
• RX 460: 350 W
• R9 380: 500 W (2×6)
• R9 370: 450 W (1×6)
• R9 285: 500 W (2×6)
• R9 280X: 550 W (1×6 + 1×8)
• R9 280: 500 W (1×6 + 1×8)
• R9 270X: 500 W (2×6)
• R7 260X: 450 W (1×6)
• HD 7790: 400 W (1×6)
• HD 7770: 350 W (1×6)
• HD 7750: 300 W

AMD Radeon (RDNA)

• RX 5700 XT: 600 W (1×6 + 1×8)
• RX 5700: 550 W (1×6 + 1×8)
• RX 5600 XT: 500 W (1×8)
• RX 5500 XT: 450 W (1×8)

AMD Radeon (RDNA 2)

• RX 6950 XT: 800 W (2×8)
• RX 6900 XT: 750 W (2×8)
• RX 6800 XT: 750 W (2×8)
• RX 6800: 600 W (2×8)
• RX 6750 XT: 600 W (1×6 + 1×8)
• RX 6700 XT: 550 W (1×6 + 1×8)
• RX 6700: 500 W (1×8)
• RX 6650 XT: 500 W (1×8)
• RX 6600 XT: 500 W (1×8)
• RX 6600: 450 W (1×8)
• RX 6500 XT: 350 W (1×6)
• RX 6400: 300 W
• RX 6300: 200 W

AMD Radeon (RDNA 3/4)

• RX7900XTX: 800 W (2×8)
• RX 7900 XT: 750 W (2×8)
• RX 7900 GRE: 650 W (2×8)
• RX 7800 XT: 600 W (2×8)
• RX 7700 XT: 550 W (2×8)
• RX 7600 XT: 500 W (1×6 + 1×8)
• RX 7600: 450 W (1×8)
• RX 9070 XT: 750 W (2×8; some models 3×8)
• RX 9070: 650 W (2×8)
• RX 9070 GRE: 600 W (2×8)
• RX 9060 XT: 500 W (1×8)
• RX 9060: 450 W (1×8)

NVIDIA GeForce (Maxwell/Pascal)

• GTX TITAN: 600 W (1×6 + 1×8)
• 980 GTX Ti: 600 W (1×6 + 1×8)
• GTX 980: 500 W (2×6)
• GTX 970: 500 W (2×6)
• GTX 960: 400 W (1×6)
• GTX 950: 350 W (1×6)
• 750 GTX Ti: 350 W
• GTX 750: 300 W
• GT 740: 250 W
• GT 730: 200 W
• 1080 GTX Ti: 600 W (1×8 + 1×6)
• GTX 1080: 500 W (1×8)
• 1070 GTX Ti: 500 W (1×8)
• GTX 1070: 500 W (1×8)
• GTX 1060: 400 W (1×6)
• 1050 GTX Ti: 350 W (1×6)
• GTX 1050: 300 W
• GT 1030: 250 W

NVIDIA GeForce (Turing/Ampere/Ada/Blackwell)

• RTX 2080 Ti: 650 W (2×8)
• RTX 2080(S): 600 W (1×8 + 1×6)
• RTX 2070(S): 550 W (1×8 or 1×8 + 1×6)
• RTX 2060(S): 500–550 W (1×8)
• GTX 1660(Ti/S): 450 W (1×8)
• GTX 1650(S): 300–350 W (some 1×6)
• RTX 3090 Ti: 850 W (3×8 → 16-pin adapter or native 16-pin)
• RTX 3090/3080 Ti: 750 W (2×8 → 16 pins)
• RTX 3080: 700 W (2×8 → 16 pins)
• RTX 3070 Ti: 650 W (2×8 → 16 pins)
• RTX 3070: 600 W (1×8 → 16 pins)
• RTX 3060 Ti: 550 W (1×8 → 16 pins)
• RTX 3060: 500 W (1×8)
• RTX 3050: 400 W (1×8) | 6 GB: 300 W
• RTX 4090: 850 W (16 pin or 4×8 → 16 pin)
• RTX 4080(S): 700 W (16 pin or 3×8 → 16 pin)
• RTX 4070 Ti(S): 600 W (16 pin or 2×8 → 16 pin)
• RTX 4070(S): 550 W (16 pin or 2×8 → 16 pin)
• RTX 4060 Ti: 450 W (1×8)
• RTX 4060: 350 W (1×8)
• RTX 5050: 400 W (1×8)
• RTX 5060: 450 W (1×8)
• RTX 5060 Ti: 500 W (1×8)
• RTX 5070: 650 W (1×16 pin 300 W or 2×8 → 16 pin)
• RTX 5070 Ti: 750 W (1×16 pin 300 W or 2×8 → 16 pin)
• RTX 5080: 850 W (1×16 pin 450 W or 3×8 → 16 pin)
• RTX 5090: 1000 W (1×16 pin 600 W or 4×8 → 16 pin)

Intel Arc (Xe Alchemist/Xe2 Battlemage)

• Bow A770: 600 W (1×6 + 1×8)
• Bow A750: 550 W (1×6 + 1×8)
• Bow A580: 450 W (2×8)
• Bow A380: 300 W (1×8)
• Bow A310: 200 W
• Arc B580: 500 W (1×8)
• Arc B570: 450 W (1×8)

Recommended PSU models (for guidance only)

Some solid examples by range, with good value for moneyPrices change, take it as a reference.

• Budget-friendly low-end rangeCooler Master 650W 80 Plus Bronze; MSI MAG A650BN 80 Plus Bronze. Suitable for up to ~RTX 5070 / RX 9070 in modest systems.
• Budget mid-range: Corsair RM750e 80 Plus Gold (with 12V-2×6); Seasonic G12 GC-750 Gold.
• Mid-range: GIGABYTE Aorus P850W Gold; ASUS TUF Gaming 1000 W Gold (clearance for top GPUs).
• High-end: GIGABYTE GP-AP1200PM 1200 W Platinum; Corsair HX1500i 1500 W Platinum (total peace of mind for extreme scenarios).

In terms of brands, they are also safe bets. Seasonic PRIME TX/HXBe still! Straight Power/Pure Power and EVGA SuperNOVA in their Gold/Platinum/Titanium ranges.

Instalation and maintenance

Position the PSU with the fan where the case provides it (often downwards with a filter) to draw in fresh air. Manage the cables well to avoid blocking the flow and use the four anchor screws.

Every 3–6 months, clean the grilles and filter with compressed air. Avoid dust, humidity and heatConsider using a power strip with surge protection if your network is unstable.

During long stops, use the rear switch or unplug from the wall: algunas PSUs they remain on standby even with the PC turned off. And avoid excessively bending the 12V-2x6 cable at the connector output.

With all of the above, you now have a clear roadmap: Calculate the wattage carefully, allowing for peak performance.Prioritize a Gold or higher motherboard with ATX 3.0/3.1 standard and a native 12V-2x6 connector, verify that it has the connectors you will use today and tomorrow, and make sure it includes complete protections and quality components. If you also choose a modular design and adjust the form factor to your case, you'll have a quiet, efficient, and reliable power supply that will last for years and ensure all your hardware performs as it should.