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- Gigabyte guide
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- 2026, gigabyte, atx 3.1, power supplies, 80 plus gold, psu
How to choose a power supply? A complete beginner's guide
The power supply (PSU – Power Supply Unit) converts mains voltage into the voltages the computer's components need. It is one of the most important but most often underestimated parts of a computer: it determines whether the computer runs stably, whether there's enough power for the graphics card and whether components are protected from voltage spikes.
In this guide we explain how power supplies differ, what 80 PLUS certificates mean, what a modular unit is, how to calculate the wattage you need and which Gigabyte power supply to choose for your graphics card.
🎯 Quick answer: what wattage power supply do you need?
| Computer type | Recommended wattage | Gigabyte example |
|---|---|---|
| Office computer, integrated graphics or GT 710 / GT 1030 | 450–550 W | P550SS 550W 80 PLUS Silver |
| Entry-level gaming PC (RTX 3050, RTX 5050, RTX 5060, RX 9060 XT) | 550–650 W | P650G PG5 650W 80 PLUS Gold |
| Mid-range gaming PC (RTX 5060 Ti, RTX 5070, RX 9070) | 650–750 W | UD750GM PG5 V2 750W 80 PLUS Gold |
| Powerful gaming PC (RTX 5070 Ti, RX 9070 XT, RTX 5080) | 850 W | UD850GM PG5 V2 850W 80 PLUS Gold |
| Enthusiast PC (RTX 5090, the most powerful processors) | 1000 W and more | UD1000GM PG5 V2 1000W 80 PLUS Gold |
Indicative values. The most accurate information is the power supply wattage recommended by the graphics card manufacturer in its specifications.
Why shouldn't you skimp on the power supply?
A cheap or underpowered power supply is a common reason why a computer suddenly shuts down, restarts or runs unstably during gaming. In the worst case, a poor-quality unit can damage other, much more expensive components.
A quality power supply has protection against voltage and current spikes, short circuits and overheating. For example, for the Gigabyte UD…GM PG5 V2 series the manufacturer lists OVP, OPP, SCP, UVP, OCP and OTP protection.
💡 What do the protection abbreviations mean?
- OVP – over-voltage protection
- UVP – under-voltage protection
- OCP – over-current protection
- OPP – over-power protection
- SCP – short-circuit protection
- OTP – over-temperature protection
How to calculate the power supply wattage you need?
- Start with the graphics card. Its manufacturer specifies the recommended power supply wattage for the whole computer. For example, the Gigabyte RTX 5060 GAMING OC – 550 W, the Gigabyte RX 9060 XT GAMING OC ICE – 450 W.
- Assess the processor. Powerful processors (Ryzen 9, Core Ultra 9) use considerably more power than a Ryzen 5 or Core Ultra 5.
- Add headroom. Choose a unit with 20–30% power headroom – it will run quieter, cooler and more efficiently, and you'll be able to fit a more powerful graphics card in the future.
- Check the connectors. Whether the unit has as many and the right kind of graphics card power connectors as your card needs.
💡 Tip
If you're torn between two wattages – choose the higher one. For example, for an RTX 5070 computer a 750 W unit will leave headroom for future upgrades.
80 PLUS certificates: Bronze, Silver, Gold, Platinum
The 80 PLUS certificate shows a power supply's efficiency – what share of the energy drawn from the mains actually reaches the computer and how much turns into heat. The higher the level, the less energy is lost, the lower the electricity bills and the less heat.
| Certificate | Efficiency | Gigabyte examples |
|---|---|---|
| 80 PLUS (white) | Basic level | – |
| 80 PLUS Bronze | Good | P450B (on clearance) |
| 80 PLUS Silver | Better | P550SS 550W, P550SS ICE 550W |
| 80 PLUS Gold | Very good – the most popular for gaming PCs | P650G PG5, P850GM, UD750GM PG5 V2, UD850GM PG5 V2, UD1000GM PG5 V2 |
| 80 PLUS Platinum / Titanium | The highest | – |
Modular or non-modular power supply?
| Type | How it works | Advantages |
|---|---|---|
| Non-modular | All cables permanently attached | Cheaper |
| Semi-modular | Main cables attached, others connectable | Fewer unnecessary cables |
| Fully modular | All cables connected as needed | The tidiest case, better airflow, easier assembly |
The Gigabyte UD750GM, UD850GM and UD1000GM PG5 V2 are fully modular power supplies. This is convenient for beginners: you connect only the cables you need.
⚠ Very important
Never use modular cables from another power supply (or another manufacturer). Cable connector pinouts are not standardised, so the wrong cable can damage components.
What are ATX 3.1, PCIe 5.0 and the 12V-2x6 connector?
New-generation graphics cards, especially the more powerful NVIDIA RTX 50 series, are powered by the new 16-pin 12V-2x6 connector (previously called 12VHPWR). It can deliver up to 600 W through a single cable.
ATX 3.1 – the latest power supply standard, designed for these graphics cards and the short power spikes they cause. Gigabyte UD…GM PG5 V2 units comply with ATX 3.1 and have a native 16-pin cable – no adapters needed. PG5 in the name indicates readiness for PCIe 5.0-generation graphics cards.
| Connector | Used for |
|---|---|
| 24-pin (20+4 pin) ATX | Motherboard power |
| 8-pin (4+4 pin) EPS / CPU | Processor power |
| 8-pin (6+2 pin) PCIe | Power for most graphics cards |
| 16-pin 12V-2x6 | Power for powerful new-generation graphics cards |
| SATA | Power for 2.5" SSDs, HDDs and other devices |
🔗 Power supply by graphics card
| Graphics card | Recommended Gigabyte power supply |
|---|---|
| GT 710, GT 1030, RTX 3050 | P550SS 550W or white P550SS ICE 550W |
| RTX 5050, RTX 5060, RX 9060 XT | P650G PG5 650W |
| RTX 5060 Ti, RTX 5070, RX 9070 | UD750GM PG5 V2 750W or white UD750GM PG5 V2 ICE |
| RTX 5070 Ti, RX 9070 XT | UD850GM PG5 V2 850W or white UD850GM PG5 V2 ICE |
| RTX 5080 | UD850GM PG5 V2 850W or UD1000GM PG5 V2 1000W |
| RTX 5090 | UD1000GM PG5 V2 1000W or white UD1000GM PG5 V2 ICE |
You'll find a more detailed description of graphics cards and their power requirements in the graphics card guide.
What else is worth knowing?
- Size. Most units are ATX format, but check that the unit will fit in your case. For example, the Gigabyte UD850GM PG5 V2 measures 150 × 140 × 86 mm.
- Fan. A larger fan (e.g. 120 mm) can spin slower and quieter.
- Colour. ICE versions are white – suitable for a light-coloured PC.
- Warranty. Quality power supplies often have a longer warranty – a sign of the manufacturer's confidence in the product.
✅ Checklist before buying
- ☐ What power supply wattage does my graphics card manufacturer recommend?
- ☐ Do I have 20–30% power headroom?
- ☐ Does the unit have the graphics card connectors I need (6+2 pin or 12V-2x6)?
- ☐ Which 80 PLUS certificate (at least Gold is recommended for gaming)?
- ☐ Do I want a modular unit?
- ☐ Will the unit fit in the case?
Frequently asked questions
Does a more powerful unit use more electricity?
No. The computer draws as much energy as it needs. A 1000 W unit with a weak computer won't use 1000 W.
Is 650 W enough for an RTX 5070?
NVIDIA specifies 650 W for the reference card, but for OC versions and more powerful processors we recommend 750 W.
Can I keep my old power supply when changing the graphics card?
Only if its wattage and connectors meet the new card's requirements and the unit isn't very old.
Do I need an adapter for the 16-pin connector?
With Gigabyte UD…GM PG5 V2 units – no, they have a native 12V-2x6 cable.