TechFuel HQ650W. That is NVIDIA’s own minimum system power figure for the RTX 5070, a card rated at 250W total graphics power, and for most builds it is the right number to buy rather than a bare floor. Where it stops being right is a 200W-plus processor or a planned upgrade to a bigger card — both push you to 750W. A genuinely efficient build can sit on 550W, with one caveat worth knowing before you shop.
Here is where each of those numbers comes from.
The card’s actual power specification
| Specification | RTX 5070 |
|---|---|
| Total graphics power (TGP) | 250W |
| NVIDIA required system power | 650W |
| Power connectors | 2x PCIe 8-pin (adapter in box), or one 300W-or-greater PCIe Gen 5 cable |
Two things in that table matter more than the headline. First, the 250W is the card, while the 650W is the system — NVIDIA’s figure already carries an allowance for a processor, drives, and fans, which is why it lands 400W above the card itself. Second, the 5070 does not force you onto a 12V-2x6 cable: it ships with an adapter for two ordinary 8-pin PCIe connectors, so an older quality supply is still in play.
What a 5070 build actually draws
The graphics card is the biggest single number but not the whole story, and the processor swings the total more than anything else. Summing real component draw the way our PSU calculator does — 45W for an ATX motherboard, 5W per RAM stick, 8W for a Gen4 M.2 drive, 2W per case fan, 12W for an AIO, plus a 10W miscellaneous allowance — a reference build of two RAM sticks, one M.2 drive, four fans and an AIO adds 93W on top of the card and processor. That puts a 5070 build here:
| Your processor | Example | System peak | Smallest PSU that works | Comfortable choice |
|---|---|---|---|---|
| 65W | Ryzen 5 9600X | ~408W | 550W | 650W |
| 120W | Ryzen 7 7800X3D | ~463W | 650W | 750W |
| 170W | Ryzen 9 9950X | ~513W | 650W | 750W |
| 250W | Core i9-14900K, unrestricted | ~593W | 750W | 850W |
“Smallest that works” is peak draw plus a 20% margin, rounded up to a size actually sold. “Comfortable” is one size above that, putting your peak near 60-70% of the rating — workable and quiet, with room for a future card. Worth knowing if you also run the tool: its headline recommendation targets nearer half load, so it will suggest a larger unit than this column. Both are defensible; this table is the smaller, cheaper end of the range.
Whether a given processor will hold the card back in games is a separate question from what it costs you in watts — the PC bottleneck calculator answers that one for a specific pairing.
Notice that the mainstream gaming row lands exactly on NVIDIA’s 650W — a useful cross-check on the arithmetic, though NVIDIA does not publish the build behind its figure. Vendor minimums tend to be deliberately worst-case, so treat the agreement as confirmation rather than as proof they assumed this exact build. Either way, the recommendation moves the moment your CPU does.
When 650W is not the answer
Go to 750W if your CPU is a flagship. A 9950X or an unrestricted 14900K can pull more than double what an X3D gaming chip draws, and that difference lands entirely on your power budget. The 250W row above peaks at 593W — on a 650W unit that is 91% load, past the point where a supply is working hard enough to get loud and to risk tripping protection.
Go to 750W if you plan to upgrade the card. A 5070 Ti is a 300W card and NVIDIA’s minimum for it is 750W — so that upgrade costs you nothing extra if you buy 750W now. A 5080 is different: 360W, and NVIDIA asks for 850W, so stepping up to one is a power-supply purchase as well as a card purchase. If you are weighing that decision now, the RTX 5070 vs 5070 Ti comparison covers what the extra 50W buys you.
You can consider 550W if the build is genuinely lean — an efficient 65W processor, one drive, no AIO. The arithmetic supports it — that build peaks near 394W, which a 550W unit covers with margin. The practical caveat is a shopping one rather than an electrical one: in our experience shopping the category, quality ATX 3.x units below 650W are thin on the ground, so the 550W shelf skews older. If a good 550W and a good 650W are twenty dollars apart, take the 650W.
Transient spikes, honestly
Graphics cards draw in bursts rather than a flat line, and this is where PSU advice usually turns into “buy double.” It should not.
Intel’s ATX 3.0 design guide requires a compliant unit to survive excursions up to 200% of its rated wattage for 100 microseconds, with lower brackets for longer events. That headroom is already in the standard, but only under both conditions at once: the unit must be above 450W and ship a native 12V-2x6 connector. A 650W supply with that cable meets the bar; a 650W supply without one does not. Smaller units, or ones lacking the connector, are held to a lower requirement.
The practical translation for a 5070: on a compliant modern unit, size for your sustained peak plus the headroom in the table above and stop padding for spikes. On an older ATX 2.x supply, leave more room, because it was never designed against those brackets. The full methodology, including where every coefficient comes from, is published on the PSU calculator.
The connector
The 5070 accepts either two PCIe 8-pin cables — an adapter is in the box — or a single PCIe Gen 5 cable rated 300W or higher. Neither is more “correct”; the native Gen 5 cable is simply tidier and avoids stacking an adapter behind the card.
If you use the 12V-2x6 connector, seat it fully until it clicks and do not put a sharp bend right at the plug. The current design shortens the sense pins specifically so that a plug which is not fully seated fails to deliver full power rather than making partial, high-resistance contact.
If you already own the power supply
Check the label on the unit itself rather than guessing from the case badge. Most supplies report nothing to Windows — there is no standard sensor for it — so the label is the reliable answer; only high-end units with digital monitoring report telemetry, and then through their own software. What you want is the continuous 12V rating, not the peak sticker number. If the unit is multi-rail, follow the manual’s rail distribution and give the card its own cables instead of daisy-chaining one pigtail.
A supply that is merely old is not automatically a problem, but one that is failing looks a lot like one that is undersized — random shutdowns under load, reboots in games. PSU failure symptoms covers how to tell those two apart before you spend money on the wrong fix.
Lowering the number
Undervolting is the one free lever here. Dropping a card’s voltage cuts real wattage while holding clocks, and the effect is big enough to matter: at the roughly 50W our own results database reports for a mid-range card, the 120W-CPU build above falls from 463W to 413W — enough to drop it a PSU size — while running cooler and quieter. The complete GPU undervolting guide covers the method, and our undervolt results database lists what other owners actually measured card by card.
For where the 5070 sits against its alternatives on raw speed, see the GPU hierarchy; for the AMD side of this decision, the RTX 5070 vs RX 9070 comparison covers both power and performance.
Sources
- NVIDIA GeForce RTX 5070 official specifications — total graphics power, required system power, and supplementary power connectors — RTX 5070 family specifications, verified live 2026-07-25. The RTX 5070 Ti figures (300W, 750W) come from the same page.
- NVIDIA GeForce RTX 5080 official specifications — the 360W total graphics power and 850W required system power cited in the upgrade section — RTX 5080 specifications, verified live 2026-07-25.
- Intel ATX 3.0 desktop power supply design guide — the power-excursion brackets and the wattage/connector conditions that qualify a unit for them (Intel ATX 3.0 PSU power excursion).
- Component draw coefficients and the sizing rules used in the build table are this site’s own published figures, listed in full in the PSU calculator methodology.