ATX 3.1 Power Supplies for RTX 50-Series GPUs: Corsair RM1000x, Seasonic Vertex GX-1000, MSI MPG A1000G and be quiet! Straight Power 12
How to size a power supply for a high-end RTX 50-series build, why native 12V-2x6 cables matter, and four 1000W units to compare.
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How to size a power supply for a high-end RTX 50-series build, why native 12V-2x6 cables matter, and four 1000W units to compare.
Photo by Victor Korniyenko / Wikimedia Commons / CC BY-SA 3.0
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High-end RTX 50-series cards draw a lot of power, and they connect through the 12V-2x6 cable (the revised version of 12VHPWR). This guide explains how to size a power supply for one, what to look for, and lists four 1000W ATX 3.1 units to compare.
Estimate your wattage, then add headroom
Add up the rated power of your CPU and GPU plus around 100W for the rest of the system; our guide to estimating PSU wattage walks through it. Then choose a unit with headroom above that estimate. Modern GPUs can spike above their rated power for a few milliseconds, and power supplies are most efficient and quietest well below their maximum load. For an RTX 5080 build, follow NVIDIA’s recommended PSU wattage at minimum. RTX 5090 builds usually call for 1000W or more.
Why native 12V-2x6 cables matter
ATX 3.1 power supplies come with a native 12V-2x6 cable that plugs straight into the graphics card. That is tidier and more reliable than the adapter that ships with the GPU. Whichever you use, push the connector fully in until it clicks with no gap, and avoid bending the cable sharply right at the connector.
Four 1000W units to compare
- Corsair RM1000x: a popular, fully modular unit with a quiet fan profile at low loads.
- Seasonic Vertex GX-1000: from a long-established power supply maker that also builds units for other brands.
- MSI MPG A1000G PCIE5: a mainstream ATX 3.x unit with a native GPU cable.
- be quiet! Straight Power 12 1000W: aimed at quiet builds.
Check the exact version in the listing (ATX 3.0 or 3.1, and which GPU cable is included), since brands refresh models under the same name.
What else to check
- Efficiency rating: 80 Plus Gold or better, or a Cybenetics rating, is a sensible baseline.
- Warranty: longer warranties usually signal confidence in the parts inside.
- Size: some 1000W units are longer than standard ATX. Check your case’s PSU clearance.
- Reviews from PSU specialists: detailed reviews measure ripple, voltage regulation and protections, which spec sheets don’t show.
Bottom line
Size the unit from your parts’ power draw plus headroom, choose a reputable ATX 3.1 model with a native GPU cable, and seat that cable properly.
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Affiliate links.As an Amazon Associate I earn from qualifying purchases. Links below go to Amazon; prices and availability change, so check Amazon for current pricing.Affiliate disclosure
Illustrative photos: Photo by Victor Korniyenko / Wikimedia Commons / CC BY-SA 3.0; Photo by Baran Ivo / Wikimedia Commons / Public domain