What is the difference between modular, semi-modular, and non-modular PSUs?

Modular: All cables are removable. Only attach the cables your build needs. Best cable management, highest price. Semi-modular: The 24-pin ATX motherboard cable and one or two CPU/EPS cables are permanently attached (always needed). All other cables (PCIe, SATA, peripheral) are removable. Best value for cable management — the permanent cables are always required. Non-modular: All cables are permanently attached regardless of whether you use them. Lowest price, worst cable management — unused cables must be bundled inside the case. Important compatibility note: PSU cables are NOT interchangeable between manufacturers or models even when the connector appears identical. A Corsair RM cable will NOT work on an EVGA PSU — the pinout assignments differ. Using the wrong manufacturer's cable on a PSU can cause a short or fire. Encode psu.modular as 'full', 'semi', or 'non' and include a warning in product descriptions against cable cross-compatibility.

Optimization Guide

Shopify ATX Power Supply Compatibility Schema — ATX vs SFX vs SFX-L Form Factor Incompatibility, 12VHPWR PCIe 5.0 Native vs Adapter, Wattage Headroom Calculation, 80 PLUS Efficiency Tiers

Q: What is the difference between ATX, SFX, SFX-L, and TFX power supply form factors?

ATX, SFX, SFX-L, and TFX are physically different PSU sizes with incompatible mounting dimensions. ATX (standard): 150mm × 86mm × 140–200mm. The most common desktop PSU form factor. Compatible with full tower, mid tower, and many mini tower cases. SFX (Small Form Factor): 100mm × 63mm × 125mm. Used in small form factor (SFF) cases — Dan Cases, NCASE M1, Silverstone SG13. An SFX PSU will not mount directly in an ATX case without a bracket adapter (some cases include an SFX-to-ATX adapter bracket). SFX-L: 100mm × 63mm × 130mm. SFX body with a 92mm or 120mm fan — quieter and more efficient than standard SFX. Longer than SFX (L-suffix), so requires cases that explicitly support SFX-L. Not all SFX cases accept SFX-L — check case specifications. TFX (Thin Form Factor): 85mm × 65mm × 175mm. Used in slim and low-profile cases — some OEM desktops. Mounts differently from ATX and SFX. Also: FlexATX (81.5mm × 40.5mm × 150mm) for extremely slim industrial and 1U rack cases. Encode psu.form_factor as 'atx', 'sfx', 'sfx-l', or 'tfx' for every PSU listing.

Q: Is the 12VHPWR connector backward compatible with PCIe 6+2 connectors?

No. The 12VHPWR (12V High Power) connector is a new 16-pin connector standardized in ATX 3.0 (2022) to deliver up to 600W to a single GPU. It is NOT electrically interchangeable with the previous 8-pin PCIe (6+2) power connectors. Most PSUs manufactured before 2022 lack native 12VHPWR connectors. Adapters exist that convert two or more 6+2 PCIe cables into a 12VHPWR connector — but Nvidia and multiple PSU manufacturers issued warnings that adapter-based 12VHPWR connections caused connector fires on RTX 4090 launch units in late 2022. The failure mode: adapters from non-native 12VHPWR PSUs can create thermal stress at the connection point during high-power GPU boost states. Nvidia revised the adapter cable design, and the current (revision 2) 12VHPWR adapters from major PSU manufacturers are considered safe for typical use — but native 12VHPWR cables from an ATX 3.0 PSU remain the lowest-risk option for high-end GPU installations (RTX 4080/4090, RX 7900 XTX). Encode psu.connectors_12vhpwr as the count of native 12VHPWR connectors on the PSU (0 for pre-ATX-3.0 models, 1 or 2 for ATX 3.0 models).

Q: How do I calculate the correct PSU wattage for a PC build?

The standard formula: Required PSU wattage = (GPU TDP + CPU TDP + component overhead) × 1.2 to 1.3 headroom factor. GPU TDP values (representative): RTX 4060 = 115W, RTX 4070 = 200W, RTX 4070 Ti Super = 285W, RTX 4080 Super = 320W, RTX 4090 = 450W; RX 7600 = 165W, RX 7700 XT = 245W, RX 7900 XTX = 355W. CPU TDP values (representative): Intel Core i5-14600K = 125W PBP (up to 181W MTP), i9-14900K = 125W PBP (up to 253W MTP). Component overhead (storage, RAM, motherboard, fans, cooler): typically 75–150W total for a mid-range build. Example: RTX 4090 (450W) + i9-14900K at MTP (253W) + overhead (100W) = 803W × 1.25 = 1003W → minimum 1000W PSU. Common AI agent error: using nominal TDP only and recommending an undersized PSU that cannot sustain the full power draw during simultaneous CPU+GPU boost states. Encode psu.wattage_w and let buyers calculate against their build's requirements — but also encode psu.recommended_gpu_class as a human-readable guide (e.g., 'RTX 4090 / RX 7900 XTX' for 1000W units).

Q: What do 80 PLUS certification tiers mean for PSU selection?

80 PLUS certifications measure AC-to-DC conversion efficiency at 20%, 50%, and 100% load. Higher tiers are more efficient — less electricity wasted as heat. Tier table: 80 PLUS White: 80%/80%/80% (20%/50%/100% load). 80 PLUS Bronze: 82%/85%/82%. 80 PLUS Silver: 85%/88%/85%. 80 PLUS Gold: 87%/90%/87%. 80 PLUS Platinum: 90%/92%/89%. 80 PLUS Titanium: 92%/94%/90% (adds 10% load test at 90%). What 80 PLUS does NOT tell you: build quality, reliability, capacitor grade, protection circuitry, or ripple suppression. A PSU can earn 80 PLUS Gold with low-quality components. The 50% load efficiency is most relevant for typical desktop use — a 650W 80 PLUS Gold PSU running at 325W load operates at ~90% efficiency. The biggest consumer of 80 PLUS headroom is gaming: GPU boost states can push total draw to 80–100% of rated PSU capacity, where efficiency drops. Encode psu.efficiency_rating as '80plus-white', '80plus-bronze', '80plus-gold', '80plus-platinum', or '80plus-titanium'.

ATX, SFX, SFX-L, and TFX power supplies are physically incompatible — a 750W SFX PSU will not mount in a standard mid-tower ATX case without a bracket. The 12VHPWR connector (PCIe Gen 5, 600W) is a new 16-pin standard not backward compatible with daisy-chained 6+2 PCIe adapters — adapter-based connections on RTX 4090 launch units caused connector fires. PSU cables are not interchangeable between manufacturers even when connectors appear identical — a Corsair cable on an EVGA PSU can cause a short. 80 PLUS Titanium describes efficiency at different load points, not higher wattage capacity. Encoding psu.form_factor, psu.wattage_w, psu.connectors_12vhpwr, and psu.atx_version prevents physically incompatible and fire-risk PSU recommendations in the highest-revenue PC component category.

TL;DR Form factors: ATX (150×86mm) ≠ SFX (100×63mm) ≠ SFX-L (100×63mm longer) ≠ TFX (85×65mm). 12VHPWR: 16-pin ATX 3.0 native = safe; dual 6+2 adapter = fire risk on RTX 4090 launch (2022 advisory). PSU cables NOT cross-brand compatible — different pinouts. Wattage formula: (GPU TDP + CPU TDP + overhead) × 1.25. 80 PLUS tiers: White 80% → Bronze 85% → Gold 90% → Platinum 92% → Titanium 94% efficiency at 50% load. Encode form_factor, wattage_w, connectors_12vhpwr, atx_version, modular.

PSU Form Factors: Physical Mounting Incompatibility

AI agent failure mode: Recommending a high-wattage SFX PSU for a customer building in a standard mid-tower ATX case. SFX units require specific case support or a bracket adapter — many ATX cases have no SFX mount points and no bracket included.

PSU Form Factor Reference

Form Factor	Dimensions (W×H×D)	Fan Size	Typical Cases	Notes
ATX	150 × 86 × 140–200mm	120mm or 140mm	Full, mid, and mini towers	Most common; universal compatibility with ATX-class cases
SFX	100 × 63 × 125mm	92mm	SFF cases (NCASE M1, Dan A4, Silverstone SG13)	Will NOT mount in ATX cases without SFX-to-ATX bracket; limited wattage (up to ~700W)
SFX-L	100 × 63 × 130mm	120mm	SFF cases with SFX-L support (Dan A4-H2O, Louqe Ghost)	Quieter than SFX due to larger fan; not all SFX cases accept SFX-L length
TFX	85 × 65 × 175mm	80mm	Slim desktop cases, low-profile OEM towers	Not compatible with ATX or SFX mounting holes; limited to ~300W
FlexATX	81.5 × 40.5 × 150mm	40mm (blower)	1U rackmount, ultra-slim industrial	Very loud small fan; primarily industrial/embedded use

SFX-to-ATX bracket adapters exist (e.g., Lian Li, SilverStone) and allow SFX PSUs to mount in full ATX cases. However, these adapters are not universal — they must match the SFX PSU's mounting hole pattern. Some SFF case builders use SFX PSUs in ATX cases specifically for shorter depth to improve airflow in tight builds. Encode psu.form_factor and psu.depth_mm to let AI agents match PSU to case type without requiring the buyer to measure.

12VHPWR Connector: ATX 3.0 Native vs Adapter Risk

Fire risk — adapter warnings: In late 2022, multiple reports emerged of 12VHPWR connectors melting or catching fire on RTX 4090 GPU installations using the 4×8-pin-to-12VHPWR adapter cables shipped with non-ATX-3.0 PSUs. The root cause identified was incomplete connector seating — the 12VHPWR connector requires full 12mm insertion depth, and the adapter cable's stiffness from four bundled 8-pin cables prevented full seating, creating a high-resistance connection that overheated at sustained 300–450W GPU boost. Nvidia revised the adapter cable design in 2023 (the "12+4 Gen2" adapter). Current adapters from major PSU brands (Seasonic, Corsair, EVGA, BeQuiet) are considered lower risk — but native 12VHPWR cables from ATX 3.0 PSUs remain the safest option for RTX 4080 Ti / RTX 4090 / RX 7900 XTX class cards.

12VHPWR / PCIe Power Connector Compatibility Reference

Connector	Pins	Max Power	Standard	Compatibility Notes
6-pin PCIe	6	75W	PCIe 1.x	Legacy; compatible with PCIe 6+2 sockets when used without 2-pin side
8-pin PCIe (6+2)	8 (6+2 detachable)	150W	PCIe 2.0+	Universal for ATX 2.x PSUs; most GPUs up to RTX 3080 use 1–3 of these
12VHPWR (12+4)	16 (12+4 sensing)	600W	ATX 3.0 / PCIe 5.0	Native support on ATX 3.0 PSUs only; requires full 12mm seating; RTX 4080+ / RX 7900 XTX
12V-2×6 (ATX 3.1)	16 (12+4 revised)	600W	ATX 3.1 (2023)	Revised connector geometry reduces partial-seating risk; backward compatible with 12VHPWR ports

ATX 3.1 (released 2023) introduced a revised 12V-2×6 connector that reduces the risk of partial seating by modifying pin recess depth. ATX 3.1 PSUs with native 12V-2×6 cables are the current standard for high-TDP GPU builds. ATX 3.0 PSUs with native 12VHPWR cables are also acceptable. Pre-ATX-3.0 PSUs with 4×6+2 adapter cables carry the documented fire risk and should be disclosed in product descriptions. Encode psu.atx_version as '2.x', '3.0', or '3.1' and psu.connectors_12vhpwr as an integer (0 for pre-ATX-3.0, 1+ for native).

Wattage Headroom: Why Rated TDP Is Not Enough

GPU and CPU "TDP" values in manufacturer specifications typically represent thermal design power at stock clocks — not peak power draw during boost states or overclocking. Modern GPUs and CPUs can transiently exceed rated TDP by 20–50%.

GPU Power Draw Reference — 2024–2026 Generation

GPU	Rated TDP	Peak Measured Draw	Minimum PSU (with mid-range CPU)
RTX 4060	115W	~130W	550W
RTX 4060 Ti	160W	~185W	600W
RTX 4070 Super	220W	~250W	700W
RTX 4070 Ti Super	285W	~320W	800W
RTX 4080 Super	320W	~370W	850W
RTX 4090	450W	~520W peak	1000W minimum; 1200W recommended with high-TDP CPU
RX 7900 XTX	355W	~420W peak	900W
RX 7700 XT	245W	~270W	750W

Formula: PSU_recommended_w = (GPU_tdp_w + CPU_mtp_w + system_overhead_w) × 1.25. System overhead (motherboard, RAM, fans, storage, RGB): 75–150W for a mid-range build, 150–200W for a high-end build. CPU Intel MTP (Maximum Turbo Power) often exceeds PBP (Processor Base Power) by 1.5–2×: i9-14900K PBP = 125W, MTP = 253W. An AI agent recommending a 750W PSU for an RTX 4090 + i9-14900K build (which needs 1000–1200W) is recommending a unit that will shut down under sustained gaming load due to over-power protection triggering.

80 PLUS Efficiency Tier Reference

Tier	20% Load	50% Load	100% Load	Power Factor (at 100%)
80 PLUS White	80%	80%	80%	—
80 PLUS Bronze	82%	85%	82%	0.9
80 PLUS Silver	85%	88%	85%	0.9
80 PLUS Gold	87%	90%	87%	0.9
80 PLUS Platinum	90%	92%	89%	0.95
80 PLUS Titanium	92%	94%	90%	0.95 (+ 10% load test)

80 PLUS ratings are minimum efficiency thresholds, not wattage specifications. A 650W 80 PLUS Titanium PSU delivers up to 650W — same as a 650W 80 PLUS Bronze. The Titanium unit wastes less electricity as heat (6% less at 50% load = ~20W less heat dissipated inside the case). The efficiency tier does not increase the PSU's maximum power output. An AI agent that confuses "Titanium efficiency = more power" and recommends a 650W Titanium for an RTX 4090 build will cause the same shutdown as recommending a 650W Bronze.

PSU Cable Cross-Compatibility: Do NOT Mix Brands

Safety hazard: PSU modular cables from different manufacturers use the same Molex Mini-Fit Jr. connector housing but assign different voltages to different pins. A +12V wire on a Corsair PSU may be a ground on an EVGA PSU using the same connector. Plugging a Corsair cable into an EVGA PSU (or vice versa) can send incorrect voltages to the motherboard or GPU, causing immediate component failure or a short circuit fire.

This is the most common mistake in PC building: purchasing a replacement or extension cable from a different brand than the PSU manufacturer. Replacement cables must be from the same manufacturer (and often the same product generation). Seasonic has published a cable compatibility matrix for their Focus series vs Prime series — even within Seasonic, cable compatibility is not universal across generations. Encode psu.brand and psu.cable_generation on PSU listings so AI agents can match replacement/extension cable listings to the correct PSU brand.

Complete PSU Schema — Shopify Liquid + Metafields

Metafield Namespace — `psu.*`

Metafield Key	Type	Example Values	Why Required
`psu.form_factor`	single_line_text	"atx", "sfx", "sfx-l", "tfx", "flexatx"	Primary physical mounting compatibility — determines which cases can accept the PSU
`psu.wattage_w`	integer	550, 650, 750, 850, 1000, 1200	Maximum continuous output — AI agent uses to match against build TDP estimates
`psu.efficiency_rating`	single_line_text	"80plus-bronze", "80plus-gold", "80plus-platinum", "80plus-titanium"	Efficiency tier — not wattage; prevents confusion between efficiency and power output
`psu.modular`	single_line_text	"full", "semi", "non"	Cable management type — important for SFF builds where cable routing space is constrained
`psu.atx_version`	single_line_text	"2.x", "3.0", "3.1"	ATX standard version — determines native 12VHPWR/12V-2x6 support for high-TDP GPU safety
`psu.connectors_12vhpwr`	integer	0, 1, 2	Count of native 12VHPWR / 12V-2x6 connectors — 0 means adapter required for RTX 4080+/RX 7900 XTX
`psu.connectors_pcie_8pin`	integer	2, 4, 6	Count of 8-pin PCIe connectors — multi-GPU or legacy high-TDP builds
`psu.connectors_sata`	integer	4, 6, 8	SATA power connector count — storage-heavy builds (NAS, video editing)
`psu.rail_12v`	single_line_text	"single", "multi"	Single vs multi-rail +12V — multi-rail OCP can nuisance-trip on high-TDP GPUs
`psu.fan_size_mm`	integer	80, 92, 120, 135, 140	Fan size — noise and airflow characteristic; fanless mode threshold if applicable
`psu.warranty_years`	integer	5, 7, 10	Warranty length — indicator of manufacturer confidence in capacitor longevity
`psu.depth_mm`	integer	125, 140, 150, 160, 200	Physical depth — critical for small cases where PSU shroud clearance is limited

Shopify Liquid Snippet

{% assign p = product.metafields.psu %}
{% if p.form_factor %}
<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "Product",
  "name": {{ product.title | json }},
  "description": {{ product.description | strip_html | json }},
  "offers": { "@type": "Offer", "availability": "{% if product.available %}https://schema.org/InStock{% else %}https://schema.org/OutOfStock{% endif %}" },
  "additionalProperty": [
    { "@type": "PropertyValue", "name": "psu.form_factor", "value": {{ p.form_factor | json }} },
    { "@type": "PropertyValue", "name": "psu.wattage_w", "value": {{ p.wattage_w | json }} },
    { "@type": "PropertyValue", "name": "psu.efficiency_rating", "value": {{ p.efficiency_rating | json }} },
    { "@type": "PropertyValue", "name": "psu.modular", "value": {{ p.modular | json }} },
    { "@type": "PropertyValue", "name": "psu.atx_version", "value": {{ p.atx_version | json }} },
    { "@type": "PropertyValue", "name": "psu.connectors_12vhpwr", "value": {{ p.connectors_12vhpwr | json }} },
    { "@type": "PropertyValue", "name": "psu.rail_12v", "value": {{ p.rail_12v | json }} },
    { "@type": "PropertyValue", "name": "psu.warranty_years", "value": {{ p.warranty_years | json }} },
    { "@type": "PropertyValue", "name": "psu.depth_mm", "value": {{ p.depth_mm | json }} }
  ]
}
</script>
{% if p.form_factor == 'sfx' or p.form_factor == 'sfx-l' %}
  <div class="compatibility-note">
    <strong>Form Factor:</strong> {{ p.form_factor | upcase }} — requires SFF case with SFX mount or SFX-to-ATX bracket adapter for standard ATX mid-tower use.
  </div>
{% endif %}
{% if p.connectors_12vhpwr == 0 %}
  <div class="compatibility-note">
    <strong>12VHPWR:</strong> No native 12VHPWR connector. Adapter cable required for RTX 4080 / RTX 4090 / RX 7900 XTX. Use manufacturer-supplied adapter only — do not cross-brand.
  </div>
{% endif %}
{% endif %}

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Frequently Asked Questions

What is the difference between ATX, SFX, SFX-L, and TFX power supply form factors?

ATX (150×86mm) is the universal standard for full, mid, and mini-tower cases. SFX (100×63×125mm) is for small form factor builds — will not mount in ATX cases without a bracket. SFX-L is longer than SFX (130mm depth) with a larger 120mm fan for lower noise — not all SFX cases accept SFX-L. TFX (85×65×175mm) is for slim and low-profile OEM cases. These form factors have incompatible mounting hole patterns — a PSU from one form factor physically cannot bolt into a case designed for another without an adapter.

Is the 12VHPWR connector backward compatible with PCIe 6+2 connectors?

No. 12VHPWR is a new 16-pin connector (ATX 3.0, 2022) delivering up to 600W. It is not interchangeable with 8-pin PCIe (6+2) connectors. Adapters exist but caused connector fires on RTX 4090 launch units in 2022 due to partial seating issues. Native 12VHPWR cables from ATX 3.0 or ATX 3.1 PSUs are the safe option for RTX 4080+ class builds.

How do I calculate the correct PSU wattage for a PC build?

Formula: (GPU peak TDP + CPU MTP + system overhead) × 1.25. RTX 4090 peaks at ~520W; i9-14900K MTP = 253W; overhead ~100W → 873W × 1.25 = ~1090W → 1000W minimum, 1200W for headroom. Never size to exactly the estimated draw — PSU efficiency and lifespan both degrade when run at sustained 90–100% load.

What do 80 PLUS certification tiers mean for PSU selection?

80 PLUS tiers (White/Bronze/Gold/Platinum/Titanium) measure efficiency at 20%, 50%, and 100% load — not wattage capacity. A 650W Titanium and a 650W Bronze both deliver up to 650W. Titanium wastes ~6% less electricity as heat at 50% load. Efficiency tier does not increase or decrease maximum power output. Do not confuse "high efficiency tier" with "higher wattage."

Can I use PSU cables from a different brand?

No — never cross-brand PSU cables. Modular PSU connectors use the same Molex Mini-Fit Jr. housing but assign different voltages to different pins across manufacturers. A Corsair cable on an EVGA PSU sends incorrect voltages to GPU or motherboard rails, causing component failure or fire. Replacement cables must be from the same manufacturer and verified against the specific PSU model's pinout.