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Lian Li SX1200P Platinum Compact ATX PSU 1200W-ATX 3.1-Black-SX1200P.B | SXP Compact ATX Form Factor, 12V-2x6 Cable, ATX 3.1 & PCIE 5.1 Compliant, Cybenetics Platinum Efficiency
Lian Li

Lian Li SX1200P Platinum Compact ATX PSU 1200W-ATX 3.1-Black-SX1200P.B

Bottom line: The Lian Li SX1200P Platinum Compact ATX PSU 1200W-ATX 3.1-Black-SX1200P.B: 1200W in a compact 150 x 86 x 140 mm ATX body for shorter PSU bays; main trade-off: 140 mm deep but still 150 mm ATX width, so not an SFX drop-in replacement.

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By , Founder & Editor-in-Chief · Listing data updated

Mike Perry — Hardware researcher since 2014. For retro PC hardware and period-correct parts, synthesises manufacturer documentation, community compatibility lists and marketplace listings rather than first-hand lab testing. Core beat: GPU performance across gaming, rendering, and local-LLM inference.

Pros & Cons

Pros

  • ✓ 1200W in a compact 150 x 86 x 140 mm ATX body for shorter PSU bays
  • ✓ Native 12V-2x6 cable plus ATX 3.1 and PCIe 5.1 compliance for current GPUs
  • ✓ Fanless mode up to 40% load keeps idle and light workloads silent
  • ✓ Up to 92% efficiency at 50% load with Platinum-rated efficiency
  • ✓ 100% Japanese 105°C-rated capacitors for stability under thermal stress

Cons

  • ✗ 140 mm deep but still 150 mm ATX width, so not an SFX drop-in replacement
  • ✗ 120 mm fan can ramp to 2,000 RPM under heavy load, so expect audible noise
  • ✗ 1200W is more than most single mid-range GPU builds need
  • ✗ Listing mixes 80 Plus and Cybenetics Platinum claims; check the exact certification

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SpecPicks Verdict

SpecPicks scored Lian Li SX1200P Platinum Compact ATX PSU 1200W-ATX 3.1-Black-SX1200P.B using a rating × review-volume × price-fit model applied to published specs and reviews across the power supplies & cables category. Lian Li's power supplies & cables lineup sits within the broader category mid-tier; price and specs are the deciding factors over brand loyalty here. Judge it on the specification table and the price rather than on sentiment: check the figures that decide your use case, then put it side-by-side with two or three close alternatives in the Compare tool before clicking through.

Common buyer scenarios for power supplies & cables of this kind: matching it to an existing build, replacing a failing part, or upgrading from a previous-generation equivalent. Check the spec table below against your current setup — particularly socket / form-factor / power-rating fields — and confirm compatibility on the retailer's listing before purchase. Prices and stock are set by the retailer and may have moved since this page was last updated.

Key Features

  • Ample PCIe 6+2 Connectors: Easily power multiple accessories, including the LIAN LI Universal USB and fan hub, ensuring a versatile setup without limitations for any build.
  • Smart Cooling Technology: Features fanless mode at ≤40% load for silent operation, while maintaining optimal temperatures during high loads for enhanced performance and longevity. Fanless mode off for excellent noise control.
  • Flexible Braided Cables: Super flexible DC cables facilitate effortless cable management, reducing clutter and improving airflow in tight or complex builds.
  • 80 Plus Platinum Certified : Achieves up to 92% efficiency at 50% load, ensuring cooler, quieter, and more energy-efficient operation with stable voltage regulation.
  • 105°C-Rated Capacitors: Built with 100% Japanese 105°C-rated capacitors for exceptional durability and stable performance, even under high thermal stress.
  • RMA Support: Missing parts or cable color issues? Reach out to us for quick support or replacement.

Full Specifications

BrandLian Li
Wattage1200 watts
Fan Count1
Dimensions150 x 86 x 140 mm
Model NameSX1200P.B
Unit Count1 Count
Form FactorATX
RMA SupportMissing parts or cable color issues? Reach out to us for quick support or replacement.
ConnectivityUSB
Model NumberSX1200P.B
Connector TypePCI Express
Cooling MethodAir
Number of Fans1
Output Wattage1200 watts
Item Dimensions5.91 x 3.39 x 5.51 inches
Mfr Part NumberSX1200P.B
Number of Items1
Compatible DevicesComputer System, Graphics Card, Processor, Motherboard, Hard Drive, Optical Drive, RAM, Case, etc.
Product Dimensions5.9"W x 3.4"H x 5.5"D (150 x 86 x 140 mm); equipped with a 120 mm FDB fan with maximum fan speed of 2,000 RPM.
Warranty Description1 year
Full listing titleLian Li SX1200P Platinum Compact ATX PSU 1200W-ATX 3.1-Black-SX1200P.B | SXP Compact ATX Form Factor, 12V-2x6 Cable, ATX 3.1 & PCIE 5.1 Compliant, Cybenetics Platinum Efficiency

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Lian Li SX1200P Platinum Compact ATX PSU 1200W-ATX 3.1-Black-SX1200P.B | SXP Compact ATX Form Factor, 12V-2x6 Cable, ATX 3.1 & PCIE 5.1 Compliant, Cybenetics Platinum Efficiency is listed on Amazon. Price, availability, shipping and returns are set by Amazon and its sellers — check the listing for current terms. SpecPicks earns a small commission on qualifying purchases — thank you for supporting independent review work.

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Lian Li SX1200P Platinum Compact ATX PSU 1200W-ATX 3.1-Black-SX1200P.B | SXP Compact ATX Form Factor, 12V-2x6 Cable, ATX 3.1 & PCIE 5.1 Compliant, Cybenetics Platinum Efficiency
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