Methodology

Every tool on this site produces an estimate, and every estimate is meant to be checked. We favor transparent, conservative math over precision we cannot honestly claim: we start from vendor-published power limits (not marketing "typical" figures), add sensible margins, and round to real-world choices. Where we assume something, we state the assumption here.

None of this is professional advice. Before buying or building, confirm every figure against the manufacturer's official specification for your exact part.

We estimate total system load as the sum of the CPU peak power, the GPU peak power, and an allowance for accessories:

estimated load = CPU peak + GPU peak + accessories

CPU peak uses the vendor's sustained ceiling (AMD PPT or Intel MTP). GPU peak uses the vendor's total graphics/board power (TGP/TBP). These are conservative worst cases; real gaming draw is usually lower.

Accessory allowances (watts) are deliberately generous engineering estimates, not measurements of any specific product:

• Motherboard: Mini-ITX 45, Micro-ATX 55, ATX 65, E-ATX 80.
• RAM: 5 per stick. SSD: 8 per drive. HDD: 10 per drive. Case fan: 3 each.
• AIO cooler: 120/140 mm 8, 240/280 mm 12, 360 mm 16.
• USB peripherals allowance (optional): 25.

We then apply headroom. The recommended minimum multiplies estimated load by a 1.1x floor. The comfortable recommendation multiplies it by 1.25x for standard use, 1.35x for light overclocking, or 1.45x for future-upgrade headroom. Headroom accounts for transient power spikes, efficiency and noise (a PSU is happiest mid-load), and capacitor aging over years of service.

Because power supplies are sold in fixed sizes, both figures are rounded up to the next common retail tier: 450, 550, 650, 750, 850, 1000, 1200, 1600 W. The tier is the number you actually buy.

The suggested 80 PLUS efficiency class is buying advice, not hardware data: small units (up to 550 W) are fine on Bronze or better; the 650-850 W range is the Gold sweet spot; at 1000 W and above, Gold or Platinum is easier to justify because efficiency losses become real watts of heat.

Pixel density (PPI) is the diagonal resolution in pixels divided by the diagonal screen size in inches:

PPI = sqrt(width² + height²) / diagonal inches

Pixel pitch is the physical distance between pixel centers: pixel pitch (mm) = 25.4 / PPI.

The retina distance is the closest distance at which a person with 20/20 vision can no longer resolve individual pixels, using the standard one-arcminute visual-acuity model: distance = 1 / (PPI × tan(1 arcminute)). Sit at or beyond it and the screen looks pixel-perfect.

The suggested comfortable range runs from the retina distance up to 1.5× that distance — closer and you may see pixel structure, farther and you stop benefiting from the resolution. It is a rule of thumb, not ergonomic or medical guidance. We also flag whether a display already looks retina at a typical desk distance of about 70 cm.

The connector checker reports the power-connector type and count our data lists for a card, its vendor-published board power, and whether an ATX 3.x power supply is worth choosing. The ATX advice is rule-based: cards with a 16-pin (12V-2x6) input get a strong ATX 3.1 recommendation; cards needing two or more 8-pin connectors get a "nice to have"; single-connector cards can use any competent modern PSU.

Because this tool only asks for the GPU, its recommended PSU range assumes a generic companion system: a 125 W-class CPU plus about 117 W of typical ATX accessories. That total is fed through the same headroom-and-tier logic as the PSU calculator. For an exact answer based on your real parts, use the PSU calculator instead.

Connector and cable-safety notes are conservative and non-modifying: seat 16-pin connectors fully, avoid adapter chains, use separate cables per connector on high-power cards, never mix modular cables between PSU models, and always confirm against your exact card and PSU documentation. We never recommend risky modifications.

These models cannot see your specific hardware, ambient temperature, overclock, cable quality, or how a particular unit behaves under transient load. They are planning aids that give you a sensible target and margin — not a guarantee of compatibility, stability, or performance.

Treat the output as a starting point, give yourself the headroom we suggest, and verify the details with the manufacturer before you spend money.