Last updated: October 21, 2026

Picking a power supply is the part of a GPU upgrade that people rush, and it is the part most likely to cause strange problems later. A PSU that is too small, too old or poorly built can cause random shutdowns under load, black screens in games, and in the worst case damage to other parts. The good news is that working out the right size is not hard once you know which numbers to look at.

This guide explains how much wattage you need for current graphics cards, why the number on the box is only half the story, and which connectors and standards matter for RTX 50 and Radeon RX 9000 series cards.

The Short Answer

For most gaming PCs with a single graphics card, these are sensible PSU sizes:

• Entry-level cards (RTX 5060, RX 9060 XT, RTX 4060): 550W to 650W
• Mid-range cards (RTX 5070, RX 9070, RTX 4070): 650W to 750W
• Upper mid-range (RTX 5070 Ti, RX 9070 XT): 750W to 850W
• High-end (RTX 5080, RX 7900 XTX, RTX 4090): 850W to 1000W
• Flagship (RTX 5090): 1000W minimum, more with a high-end CPU or overclocking

If you want a quick rule: add up your GPU’s board power and your CPU’s maximum power, add about 100W for everything else, then pick a PSU that is roughly 1.5 times that number. That leaves room for power spikes, ageing and future upgrades without paying for a unit far bigger than you need.

Why Your GPU Needs More Than Its Rated Wattage

Every graphics card has a rated power figure. NVIDIA calls it Total Graphics Power (TGP) and AMD calls it Total Board Power (TBP). The RTX 5070 Ti, for example, is rated at 300W and the RX 9070 XT at 304W for the reference design.

That number is an average under sustained gaming load. It is not the highest power the card ever draws. Modern GPUs change their clock speed and voltage many times per second, and for a few milliseconds at a time they can pull well above their rating. These short bursts are called transient spikes or power excursions.

A weak or older PSU can see one of these spikes as a fault and trip its over-current protection. The PC switches off instantly, as if someone pulled the plug. Many people who see this assume their graphics card is faulty, when the real cause is the power supply.

Factory-overclocked partner cards also draw more than reference cards. The Gigabyte RX 9070 XT Gaming OC, for example, ships with a 330W power limit instead of the 304W reference figure. Always check the spec page for your exact model, not only the GPU name.

GPU Power and Recommended PSU Table

The table below lists rated board power for popular cards and the PSU size we recommend for a typical gaming system with a mid-range or upper mid-range CPU (Core i5/i7 or Ryzen 5/7). If you use a Core i9 or Ryzen 9, move up one size.

Graphics card	Rated board power	Recommended PSU
RTX 5090	575W	1000W
RTX 5080	360W	850W
RTX 5070 Ti	300W	750W–850W
RTX 5070	250W	650W
RTX 5060 Ti	180W	550W
RTX 5060	145W	550W
RX 9070 XT	304W	750W–850W
RX 9070	220W	650W
RX 9060 XT 16GB	160W	550W
RTX 4090	450W	850W–1000W
RTX 4070	200W	550W–650W

These figures line up with the PSU tables published by power supply makers such as Corsair and with MSI’s guidance for RTX 50 series cards. NVIDIA itself lists 1000W as the minimum system power for the RTX 5090 Founders Edition.

How to Calculate Your Own PSU Size

Tables are a good starting point, but your CPU and the rest of your build make a real difference. Here is a simple method you can do with a calculator.

Step 1: Find your GPU power

Look up the TGP or TBP of your exact card on the manufacturer’s product page. Use the partner card’s figure if it is factory overclocked.

Step 2: Find your CPU power under load

Use the maximum power figure, not the base TDP. Intel lists this as Maximum Turbo Power (for example, 253W on many Core i9 chips). AMD’s PPT figure is the closest equivalent. A Ryzen 7 9800X3D draws far less than a Core i9-14900K, and this alone can change your PSU size by 150W or more.

Step 3: Add the rest of the system

Motherboard, RAM, SSDs, fans, RGB and USB devices usually add 75W to 125W combined. Use 100W if you are not sure.

Step 4: Add headroom

Multiply the total by about 1.5. Here is a worked example:

• RTX 5070 Ti: 300W
• Ryzen 7 9700X (PPT around 88W at stock): 90W
• Everything else: 100W
• Total: 490W × 1.5 = 735W, so a quality 750W unit is a good fit

Do the same sum with a Core i9-14900K (253W) instead, and you get 653W × 1.5 = 980W. In that case an 850W unit would usually work, but 1000W is the safer choice.

Why 1.5×?

Power supplies are most efficient at around 40 to 60 percent load, and they run cooler and quieter there because the fan does not need to spin as fast. A PSU that sits at 95 percent load during every gaming session will be louder, hotter and more likely to trip on spikes. The extra capacity also gives you room for one GPU upgrade later.

Wattage Is Not Everything: Quality Matters More

A cheap 850W unit can be worse than a good 650W unit. The label shows how much power the PSU claims to deliver, not how well it delivers it. Here is what to check.

Efficiency rating (80 Plus or Cybenetics)

80 Plus Bronze, Gold and Platinum ratings tell you how much power is lost as heat. Gold is the sweet spot for most gaming builds. Cybenetics is a newer, stricter testing standard that also rates noise, and many reviewers now prefer it. Keep in mind that efficiency ratings do not measure build quality or protection features.

Protection features

A good PSU should list OCP (over-current), OVP (over-voltage), UVP (under-voltage), OPP (over-power), SCP (short-circuit) and OTP (over-temperature) protection. If a unit does not list them, skip it.

Brand and platform

Many PSU brands do not build their own units. They rebadge designs from OEMs such as Seasonic, CWT, Great Wall or Channel Well. Two PSUs from the same brand can come from very different factories. Before buying, look for a review of that exact model from a reviewer who does load testing, or check a community PSU tier list.

Warranty

A long warranty is a good sign that the maker trusts the unit. Quality PSUs often come with 7 to 12 years of cover. A unit with a 2-year warranty is usually a budget design.

ATX 3.1, PCIe 5.1 and the 12V-2×6 Connector

If you are buying a new PSU for an RTX 40 or RTX 50 series card, these terms matter.

ATX 3.0 and 3.1

ATX 3.0 was the first PSU standard designed with modern GPU spikes in mind. It requires power supplies to handle short spikes of up to twice their rated output. ATX 3.1 is a small update that switched the main GPU power connector from 12VHPWR to the revised 12V-2×6 design. For a new build in 2026, an ATX 3.1 unit is the best choice.

The 12V-2×6 connector

High-end NVIDIA cards such as the RTX 5090, 5080 and 5070 Ti use a single 16-pin connector instead of several 8-pin cables. The 12V-2×6 version has shorter sense pins, so the card will not draw full power unless the plug is pushed all the way in. This was a response to melting connector reports on early 12VHPWR cards.

A few tips for this connector:

• Push the plug in until it clicks and there is no visible gap.
• Do not bend the cable sharply right at the connector. Leave a few centimetres of straight cable before any bend.
• Use the native cable from your PSU if it has one, rather than an adapter.
• If you use the adapter that came with the card, plug each 8-pin end into a separate PSU cable, not the daisy-chain end of one cable.

Many mid-range cards, including most RX 9070 XT and RTX 5060 models, still use standard 8-pin PCIe connectors. Check which connector your card uses before buying a PSU. Our guide on whether GPUs come with power cables covers what is usually in the box.

Can You Use Your Old PSU With a New GPU?

Often yes, but check these points first:

1. Wattage: Does it meet the table above with headroom to spare?
2. Age: Capacitors age, and a PSU that is 8 to 10 years old may not deliver its rated power any more. If it is past its warranty period, consider replacing it.
3. Connectors: Does it have enough PCIe 8-pin cables? Never use SATA-to-PCIe or Molex-to-PCIe adapters for a graphics card. They are not rated for that current and are a fire risk.
4. Quality: A cheap, unknown-brand unit should not be paired with an expensive GPU.

If your PC shuts off or reboots only when you start a game, and the GPU temperature is normal, the PSU is the first thing to suspect. Compare your temperatures with our normal GPU temperature ranges to rule out heat as the cause.

Signs Your PSU Is Too Weak

• The PC turns off completely under gaming load, with no blue screen
• Crashes happen at the same demanding moment in a game, such as a loading screen or big explosion
• Coil whine from the PSU itself, or a buzzing that changes with load
• Random restarts when CPU and GPU are both busy, such as while streaming
• GPU stutters or drops clocks even though temperatures are fine

Some of these symptoms overlap with other problems. Coil whine, for example, often comes from the graphics card rather than the PSU. See our article on GPU coil whine to tell the two apart.

Undervolting Can Lower Your Power Needs

If you are close to the limit of your current PSU, undervolting your graphics card is a safe way to lower its power draw. Many cards keep most of their performance while drawing noticeably less power. It is not a substitute for a properly sized PSU, but it does reduce heat and spike size. Our step-by-step GPU undervolting guide shows how to do it in MSI Afterburner and AMD Software.

Frequently Asked Questions

Is 650W enough for an RTX 5070?

Yes, for most builds. The RTX 5070 is rated at 250W, and a quality 650W unit leaves plenty of headroom with a mid-range CPU. With a Core i9 or a heavily overclocked CPU, choose 750W.

Is 750W enough for an RX 9070 XT?

A good 750W unit is enough for most RX 9070 XT builds with a Ryzen 5/7 or Core i5/i7. Partner cards with higher power limits and high-end CPUs are better served by 850W.

Do I need an ATX 3.1 PSU for an RTX 50 series card?

It is not strictly required, but it is recommended. An ATX 3.1 unit is built to handle the short power spikes these cards produce and usually includes a native 12V-2×6 cable. An older ATX 2.x unit with enough wattage and the right 8-pin cables will still work with the included adapter.

Can a too-powerful PSU damage my GPU?

No. A PSU only supplies the power that the components ask for. A 1000W unit in a system that uses 400W is simply running at low load. The only downsides are higher cost and slightly lower efficiency at very low loads.

How long does a PSU last?

A quality unit typically lasts 7 to 10 years, and the warranty length is a good hint. Budget units can degrade sooner, especially in hot or dusty rooms.

Final Thoughts

Size your PSU by adding the real power figures for your GPU and CPU, add about 100W for the rest of the system, and multiply by 1.5. Then spend just as much attention on quality as on wattage: a well-reviewed Gold unit with full protections and a long warranty is worth more than a bigger number on a cheap box. If you are building a new RTX 50 or RX 9000 system, an ATX 3.1 unit with the right connectors will save you trouble for years.

If you are also choosing the card itself, our guide on how much VRAM you need is a good next read.