Short answer: buy an ATX 3.1 power supply if you're buying new, use its native 16-pin cable rather than an adapter, and push the plug in fully at both ends without bending the cable near it.
What ATX 3 is
ATX is the standard that sets how a PC power supply should behave. Version 3.0 added a native 16-pin connector for graphics cards, called 12VHPWR, and rules for handling the short power spikes modern cards create. Version 3.1 refined it.
What changed in ATX 3.1
| ATX 3.0 | ATX 3.1 | |
|---|---|---|
| Graphics card connector | 12VHPWR | 12V-2x6 |
| Power and ground terminals | Standard length | Longer |
| Sense pins | Standard length | Shorter |
| Connector rating | 600W | 600W |
| Hold-up time | 17 ms | 12 ms |
The key change is the plug. The 12V-2x6 connector has longer power terminals and shorter sense pins. If the plug works loose, the sense pins disconnect first and the card stops drawing full power. The rating stays at 600W, so the change is about reliability, not more power.
Hold-up time is how long the power supply keeps running after a brief mains interruption. ATX 3.1 lowered the requirement, which Corsair says allows a small efficiency gain.
The melting connector problem
The 16-pin connector has a reputation for melting, first on RTX 4090 cards and then on some RTX 5090s. In June 2025, Tom's Hardware reported that 12VHPWR and 12V-2x6 connectors were still melting, and set out the main causes:
- A small safety margin. Each pin runs close to its limit at high power. Older 8-pin connectors have much larger margins, so melting from normal use is extremely rare on them.
- Uneven current across pins. Many cards don't balance current across the 12V pins, so if one contact is poor, others carry more than they should, and the card doesn't notice.
- Power near the limit. The RTX 5090's rated power has reached the connector's 600W limit.
- Fitting problems. A plug that isn't fully seated, or a cable bent hard near the connector, makes things worse.
The 12V-2x6 design helps with the fitting problem, but it doesn't remove the small safety margin. Fitting the plug carefully matters, especially on the most powerful cards.
How to fit a 16-pin plug safely
- Use the native cable that came with your ATX 3.0 or 3.1 power supply, not an adapter, where you can.
- Push it in fully at both ends until it clicks and sits flush, with no gap.
- Don't bend the cable near the plug. Tom's Hardware passes on Seasonic's guidance to avoid bending or straining it within 35mm of the connector.
- Check your case clearance before you build. If the side panel would press on the cable, consider a 90 degree cable from your power supply maker, or a roomier case.
- Plug it in as few times as possible. The connector isn't designed for many insertions. Tom's Hardware suggests replacing a cable that has been unplugged and reconnected repeatedly.
- Only use reputable replacement cables made for your exact power supply.
Do I need ATX 3.1?
Every unit on my list is ATX 3.0 or newer, so all of them handle current cards. If you're choosing between them, ATX 3.1 is the better standard. Check the product page too: some ATX 3.0 units, like the MSI MAG A850GL PCIE5, use the older 12VHPWR socket at the power supply end.
AMD cards and older cards
Not every card uses the 16-pin plug. Tom's Hardware notes it is rarely seen on AMD cards, and MSI says RX 9070 XT models use two or three 8-pin connectors, or a single 12V-2x6, depending on the model. ATX 3 power supplies still include standard 8-pin PCIe cables, so they suit older cards too.
ATX 3.1 picks
- All-rounder · Tier ACorsair RMx (2024)80 Plus Gold · Fully modular · ATX · 750/850/1000WATX 3.1 and PCIe 5.1 ready, with a 12+2 pin cable rated at 600W according to HWBusters.Check 850W price
- Tidy builds · Tier ACorsair RMx Shift80 Plus Gold · Fully modular · ATX · 750/850/1000WATX 3.1, with side sockets that keep the cable away from tight bends at the power supply end.Check 850W price
- Quiet pick · Tier Bbe quiet! Pure Power 13 M80 Plus Gold · Fully modular · ATX · 750/850/1000/1200WATX 3.1 and almost silent in lab tests.Check 850W price
- For an RTX 5090 · Tier ACorsair HXi (2025)80 Plus Platinum · Fully modular · ATX · 1200/1500WATX 3.1 with two 12V-2x6 connectors, according to Tom's Hardware.Check 1200W price
Questions
Is 12V-2x6 the same as 12VHPWR?
It is an updated version of the same 16-pin plug, with longer power terminals and shorter sense pins. Use the cable that came with your power supply.
Can I use an adapter with an RTX 50 card?
You can, but a native cable from an ATX 3.0 or 3.1 power supply means fewer connections to go wrong.
Why do 16-pin connectors melt?
Tom's Hardware points to a small safety margin per pin, uneven current across pins, power draw near the 600W limit and poor fitting.
Is ATX 3.0 still fine?
Yes. ATX 3.0 units handle current graphics cards. ATX 3.1 mainly improves the connector.
Do AMD cards use the 16-pin connector?
Rarely. Most use 8-pin connectors, though some RX 9070 XT models use a 12V-2x6.
Sources
- Corsair: ATX 3.0 vs ATX 3.1
- Tom's Hardware: why power connectors are melting, and what to do (June 2025)
- MSI: best PSU for AMD RX 9070 XT
- HWBusters: MSI MAG A850GL PCIE5 review
- Tom's Hardware: Corsair HX1200i ATX 3.1 review
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