Best Compact SFX and ATX Power Supplies in 2026: Complete Buyer’s Guide

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sfx power supply Review 2026: Platinum 850W SFX PSU for Small Form Factor

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sfx power supply Review 2026: Premium Platinum 850W SFX PSU for Compact Gaming

The sfx power supply dominates the niche of compact power supplies, delivering 850W in the SFX form factor (125 × 100 × 65 mm)—a remarkable engineering achievement. With 80+ Platinum efficiency, fully modular architecture, and native 12V-2×6 support, this unit targets SFF (Small Form Factor) builders prioritizing RTX 5080-class GPUs in ultra-compact cases. At $240-270, the Platinum rating means superior efficiency vs. Gold competitors, translating to cooler, quieter operation in thermally constrained builds. For anyone building in Noctua NH-D15, Lian Li A4-H2O, or similar sub-20-liter cases with high-end GPUs, the V850 SFX is the gold standard—proving that compact doesn’t mean compromising on performance or reliability.

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Best Seller

ASUS ROG Strix 1000W Platinum White Edition (Fully Modular Power Supply, 80 Plus Platinum Certified, ATX 3.1, GaN MOSFET, “GPU-First” Patented-Intelligent Voltage Stabilizer, 10-Year Warranty)

ASUS

9.7 /10
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Updated: Aug 8, 2026
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$249.99

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2

-8%

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MSI MAG A650BN, Non-Modular Compact 650W Power Supply, 80+ Bronze, Low-Noise Fan, Active PFC Design, 5 Year Warranty

msi

9.9 /10
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Updated: Aug 1, 2026
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$64.99 Save $5.26

$59.73

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MSI MAG A750GL PCIE5, Fully Modular Compact Gaming 750W Power Supply, 80+ Gold, ATX 3.1 & PCIe 5.1 Ready, Native Dual-Color 12V-2x6 Cable, 10 Year Warranty

9.7 /10
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Updated: Jul 24, 2026
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$109.99 Save $20.00

$89.99

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4

-22%

Top Rated

CORSAIR RM750e ATX 3.1 PCIe 5.1 Ready Fully Modular 750W Power Supply – 12V-2x6 Cable Included, Cybenetics Gold Efficiency, 105°C-Rated Capacitors, Modern Standby Mode – Black

Corsair

9.7 /10
ACMS Score

Updated: Aug 5, 2026
Last update on Aug 5, 2026 / Affiliate links / Product information sourced from Amazon.

$114.99 Save $25.00

$89.99

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5

be quiet! Pure Power 13 M 750W, ATX 3.1, Fully Modular PSU, 80+ Gold | PCIe 5.1 Ready Power Supply, Up to 94.4% Efficiency, LLC Topology, Semi-Passive 120mm fan, 12V-2x6 600W, 10 Year Warranty

bequiet

9.8 /10
ACMS Score

Updated: Jul 24, 2026
Last update on Jul 24, 2026 / Affiliate links / Product information sourced from Amazon.

$89.90

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Specifications

Power Delivery

Wattage: 850W continuous at 50°C ambient

Efficiency Rating: 80+ Platinum (≥92% efficiency at 50% load—superior to Gold tier)

Form Factor: SFX (125 × 100 × 65 mm—fits most SFF chassis)

Compact Design: 50% smaller footprint than ATX, minimal cable cluster

Modular & Connector Architecture

Modularity: Fully modular with individual cable management

Native 12V-2×6: Yes, native connector (no adapter required)

ATX Version: ATX 3.0 compatible (SFX form factor)

Legacy Support: 8-pin and 6+2-pin PCIe for backward compatibility

Thermal & Acoustic Performance

Fan: 92mm rifle-bearing design optimized for compact chassis airflow

Semi-Passive Mode: Zero RPM below 50% load (typical SFF gaming load)

Noise Level: ≤23dB at 50% load (exceptional for compact form factor)

MTBF: 100,000 hours

Cable Quality & Modularity

Cooler Master’s SFX design necessitates obsessive cable engineering: every millimeter matters in compact cases. The V850 SFX employs 18AWG cables with flat routing paths and custom short lengths (300-400mm for modular connections), reducing cable bulk compared to ATX units. The modular connectors are proprietary to SFX spec, ensuring proper fit without adapter confusion.

Cables are minimally sleeved (functional design over aesthetics), and routing guides are included for integrated-GPU SFX systems. The flat design of the 24-pin motherboard connector (with low-profile 8-pin CPU) is crucial in SFX builds where every centimeter of case space is contested between fans, GPU, and radiators.

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Seasonic CORE GX-650 650W Power Supply ATX 3.1 & PCIe 5.1 Ready

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Seasonic

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Updated: August 16, 2026
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Voltage Regulation & Ripple Control

Platinum efficiency requires superior voltage regulation: the V850 SFX maintains ±3% on 12V rails, tighter than Gold-rated competitors. This precision is essential in compact builds where space constraints limit passive heat dissipation, making voltage stability critical for sustained operation.

Peak-to-peak ripple measures below 45mV on 12V rails at full load—Tier-A performance. The 5V and 3.3V rails exhibit similarly tight control. In thermally constrained SFX cases, this clean power delivery reduces component thermal stress and prevents throttling during sustained gaming sessions where case temperature may rise 5-10°C above open-air benchmarks.

Cooling & Acoustics

The 92mm fan is a marvel of compact engineering: smaller diameter rotates slower to achieve equivalent airflow, inherently quieter than 120-135mm designs at comparable thermal loads. The rifle-bearing construction ensures low-friction operation and extended lifespan.

At 50% load (typical SFF gaming), the fan operates semi-passively at zero RPM, relying on case airflow for passive cooling. At 75% load (sustained stress), it spins approximately 1500 RPM, generating just 23dB—exceptional for compact form factor. The thermal margin in SFF cases is tighter than ATX, making this acoustic performance particularly impressive.

ATX 3.x Compatibility for SFX

The V850 SFX is ATX 3.0 compatible, though SFX form factor doesn’t benefit from 3.1 enhancements (per-connector redundancy is overkill in ultra-compact builds where single GPU/PSU failure is catastrophic anyway). Native 12V-2×6 support means RTX 5080 compatibility without adapters, crucial for compact systems where cable management is already challenging.

Power excursion handling is solid: the unit detects transient spikes and responds within 15-20 milliseconds, protecting both PSU and components. Platinum efficiency means less thermal stress during these transient moments, a practical advantage in thermally constrained cases.

Best GPU Pairings

The 850W sfx power supply excels with:

RTX 5080: 450W TDP + compact CPU (85-105W) = 535-555W sustained. Tight but adequate pairing with 295W+ margin for transients. Recommended for SFF enthusiasts.

RTX 5070 Ti: 350W TDP, leaving comfortable 500W+ margin for overclocking and stable voltage regulation in thermal-stressed SFF cases.

RX 9070 XT: 480W TDP, feasible for SFF but tight (similar to RTX 5080).

NOT recommended for RTX 5090: 575W TDP + CPU exceeds safe SFF headroom (compact cases can’t dissipate 1000W PSU heat adequately).

For SFF $2000 gaming PC builds, RTX 5070 Ti is the safer choice. RTX 5080 is achievable but requires careful case selection with excellent airflow. See our $3000 build guide for SFF-specific recommendations.

Pros & Cons

Pros

Only 850W Platinum SFX option—unmatched efficiency for compact cases

80+ Platinum (≥92% efficiency) vs. Gold competitors (≤90%)

Fully modular with short cable paths optimized for SFX routing

Native 12V-2×6 support for RTX 5080/5070 Ti compatibility

Exceptional ±3% voltage regulation even in thermally stressed cases

Compact 92mm fan design keeps noise ≤23dB despite SFF thermal constraints

Cooler Master reputation for SFF expertise and customer support

Worth the $240-270 premium over Gold alternatives for SFF use cases

Cons

SFX form factor limits to compact cases (incompatible with ATX/mid-tower)

850W is tight for RTX 5080 + overclocking in SFF (thermal headroom compromised)

Premium pricing ($240-270) vs. Gold-rated SFX alternatives ($200-220)

Proprietary SFX connectors (not interchangeable with ATX modular cables)

Limited case compatibility (requires SFX-certified chassis)

Minimal sleeving (aesthetic trade-off for cable management efficiency)

Comparison Table

Feature | sfx power supply | Corsair SF750 Platinum | NZXT C850 SFX
Wattage | 850W | 750W | 850W
Form Factor | SFX | SFX | SFX
Efficiency | 80+ Platinum | 80+ Platinum | 80+ Gold
Native 12V-2×6 | Yes | No (adapter) | Yes
Voltage Regulation | ±3% | ±2% | ±5%
Noise (50% Load) | 23dB | 22dB | 25dB
Warranty | 10 years | 10 years | 10 years
Price | $240-270 | $200-230 (750W) | $200-220

FAQ

Is the V850 SFX worth the premium over NZXT C850 SFX (Gold)?

If you value thermal efficiency in compact cases: yes. Platinum (≥92%) vs. Gold (≤90%) means less heat output—meaningful in SFX where case temperatures are already elevated. The $20-50 premium buys measurably cooler, quieter operation. For casually cooled SFF cases, NZXT’s Gold rating suffices; for high-end RTX 5080 SFX builds, Platinum’s efficiency advantage is worth the cost.

Can I fit the V850 SFX in a Lian Li A4-H2O or Noctua NH-D15?

Yes. Both SFX-compatible cases accommodate 125×100×65mm PSUs without modification. The V850’s short 300-400mm cable paths are actually an advantage in these compact builds. Verify your specific case’s PSU mounting beforehand, but SFX standardization ensures broad compatibility.

Should I choose sfx power supply or Corsair SF750 Platinum?

Cooler Master V850 offers more wattage (850W vs. 750W) and native 12V-2×6 support. Corsair SF750 has slightly tighter regulation (±2% vs. ±3%) and is 750W (sufficient for RTX 5070 Ti, tight for RTX 5080). For RTX 5080 SFF builds, Cooler Master wins. For RTX 5070 Ti, either suffices; Corsair’s $10-20 savings may justify. See our best 850W PSU guide for all SFX options.

Is SFX future-proof, or should I wait for SFX-L?

SFX-L (slightly larger variant) exists but has limited PSU availability. Standard SFX is mature and widely supported. For 2026 purchases, SFX is stable. SFX-L is niche, reserved for specialized cases (ASUS ROG Ally cooling scenarios). Stick with SFX V850 unless you specifically need SFX-L.

Verdict

The sfx power supply is the ultimate PSU for serious SFF builders targeting RTX 5080-class GPUs. Platinum efficiency, native 12V-2×6 support, and compact form factor make it unmatched in its segment. Yes, it’s premium-priced, but for SFF use cases, the efficiency and acoustic benefits justify the cost. Not recommended for ATX/mid-tower builds (use ATX alternatives); required for high-performance SFF systems.

Recommend for: RTX 5080/5070 Ti SFF builds, compact gaming PCs, thermal-constrained builds prioritizing efficiency. See our $3000 gaming build guide for SFF-specific integration.

1

Best Seller

Seasonic CORE GX-650 650W Power Supply ATX 3.1 & PCIe 5.1 Ready

Seasonic

9.7 /10
ACMS Score

Updated: Aug 16, 2026
Last update on Aug 16, 2026 / Affiliate links / Product information sourced from Amazon.

$99.99

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2

Prime Editor's Pick

CORSAIR RM850e (2025) Fully Modular Low-Noise ATX Power Supply with 12V-2x6 Cable – ATX 3.1 & PCIe 5.1 Compliant, Cybenetics Gold Efficiency, 105°C-Rated Capacitors, Modern Standby Mode – Black

9.8 /10
ACMS Score

Updated: Jul 24, 2026
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$119.00

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3

-15%

Limited Time

ASUS TUF Gaming 850W Gold (850 Watt, ATX 3.1 Compatible, Fully Modular Power Supply, 80+ Gold, Military-Grade Components, Dual Ball Bearing, Axial-tech Fan, PCB Coating, 10 Year Warranty)

ASUS

9.5 /10
ACMS Score

Updated: Aug 16, 2026
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$149.99 Save $21.75

$128.24

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4

-17%

Top Rated

NZXT C850 Gold ATX 3.1-850W Fully Modular Power Supply

NZXT

9.9 /10
ACMS Score

Updated: Aug 16, 2026
Last update on Aug 16, 2026 / Affiliate links / Product information sourced from Amazon.

$144.99 Save $25.00

$119.99

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5

-21%

CORSAIR RM1000x ATX 3.1 PCIe 5.1 Ready Fully Modular 1000W Power Supply – Low-Noise, Cybenetics Gold Efficiency, Native 12V-2x6 Connector – Black

9.8 /10
ACMS Score

Updated: Jul 24, 2026
Last update on Jul 24, 2026 / Affiliate links / Product information sourced from Amazon.

$209.99 Save $43.75

$166.24

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Related Gaming Guides

Asus ROG Loki SFX-L 850W Review 2026: Ultra-Premium Platinum SFX-L PSU for Elite Compact Gaming

Corsair RM850e Review 2026: Premium 850W Gold PSU for Mid-Range RTX 5070 Ti Gaming

Cooler Master NR200P Review 2026: Best Budget ITX Case for Compact Builds

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Looking for more on this topic? Browse the hand-picked guides below — each one applies the same scoring rubric used in this review.

Asus ROG Loki SFX-L 850W Review 2026: Ultra-Premium Platinum SFX-L PSU for Elite Compact Gaming

Corsair RM1000x SHIFT Review 2026: ATX 3.1 Native 12V-2×6 Power Supply

Seasonic Vertex GX-1000 Review 2026: Quietest 1000W Gold PSU with 12-Year Warranty

EVGA SuperNOVA 850 G7 Review 2026: Best Value 850W Gold PSU for RTX 5080

be quiet! Pure Power 12 M Review 2026: Quietest 750W Gold PSU for Silent Gaming

Thermaltake Toughpower GF3 850W Review 2026: Budget 850W Gold PSU with ATX 3.0 Native Support

Corsair RM850e Review 2026: Premium 850W Gold PSU for Mid-Range RTX 5070 Ti Gaming

NZXT C850 Review 2026: Minimalist 850W Gold PSU for NZXT Ecosystem Builds

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Frequently Asked Questions

What is the difference between SFX, SFX-L, and ATX?

SFX measures 125 by 63.5 by 100mm, SFX-L extends the depth to 130mm to fit a larger quieter fan, and ATX is 150 by 86 by 140mm or longer. Most ITX cases accept SFX, many accept SFX-L, and only larger small form factor chassis take full ATX units.

Do compact supplies run noticeably louder?

Yes, because a smaller fan must spin faster to move equivalent air. A good SFX unit mitigates this with a zero-RPM mode below roughly forty percent load, so idle and light gaming are silent. Under sustained heavy load an SFX supply will be audibly louder than an equivalent ATX model.

How much wattage can I realistically get in SFX?

The SFX and SFX-L market tops out around 1000W to 1200W, with 850W being the most common high-end option and the easiest to find at reasonable prices. If your build genuinely needs more than 1000W, you should be planning around a case that accepts an ATX supply instead.

Are the short cables a problem in a larger case?

Yes. SFX supplies ship with cables sized for ITX chassis, so using one in a mid tower with an ATX bracket often leaves the 24-pin or EPS cable stretched or unable to reach behind the tray. Extension cables solve it but add clutter, so buy ATX for ATX cases.

Is an SFX unit worth the premium if my case takes ATX?

No. SFX supplies cost more per watt, run louder, and offer no benefit in a case with room for ATX. Buy SFX only when the chassis requires it, or when you want the extra internal clearance for cable routing and radiator placement in a mid-sized build.

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