Lian Li SX Platinum 1200W SXP Compact ATX Form Factor Power Supply w/ 12V-2x6 Cable - ATX 3.1 & PCIE 5.1 Compliant - 140mm Fan - Full Modular - 10 Year Warranty - White (SX1200P.W)
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AI Verdict
This 1200W ATX 3.1 and PCIe 5.1 compliant power supply with 105°C Japanese capacitors and a 140mm depth is for builders prioritizing compact size and high efficiency.
This power supply is a strong fit for users building compact, high-performance systems that demand 1200 watts and the latest ATX 3.1 and PCIe 5.1 standards. Its 140mm depth directly addresses space constraints in smaller cases.
If 1200W is overkill, look for lower wattage ATX 3.1 PSUs with similar compact dimensions to save money.
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Pros
- Delivers 1200 watts of power, supporting ATX 3.1 and PCIe 5.1 standards with a 12V-2x6 cable.
- Achieves up to 92-94% efficiency at 50% load, holding an 80 Plus Platinum certification.
- Features a fanless mode for silent operation when under 40% load.
- Built with 100% Japanese 105°C-rated capacitors for durability.
- Its compact 140mm depth allows for wider case compatibility and improved cable routing space.
- Includes flexible braided cables with cable combs for easier management.
Cons
- The white cables may have a blue/purple tint, requiring a free replacement from Lian Li for pure white.
- The 120mm fan is smaller than some higher-end PSUs, potentially impacting cooling under extreme loads compared to larger fans.
- Despite 80 Plus Platinum certification, Cybenetics certification details were not available at the time of some reviews.
Dimension Scores
The 1200W output combined with 80 Plus Platinum certification (up to 92-94% efficiency) and ATX 3.1/PCIe 5.1 compliance places it at the top tier for power delivery and energy conservation.
The fanless mode at <=40% load ensures silent operation for most daily tasks, and the 120mm fluid dynamic bearing fan is noted for quiet performance.
It uses 100% Japanese 105°C-rated capacitors and high-current copper alloy terminals, indicating a focus on long-term stability and durability.
The fully modular design, flexible braided cables, and included cable combs significantly simplify cable routing and reduce clutter.
Best For
- Compact PC builds where PSU depth is a critical factor for space.
- High-end gaming systems requiring 1200W and ATX 3.1/PCIe 5.1 compliance for next-gen GPUs.
- Users who prioritize quiet operation with its fanless mode at low loads.
Not Recommended For
- Budget-focused builds, given its mid-range price band and Platinum efficiency.
- Users unwilling to potentially request replacement cables for color accuracy.
Watch Out For
- The included white braided cables might have a blue/purple tinge, which means you might need to contact Lian Li for free pure white replacements.
- While 80 Plus Platinum certified, some reviews noted the absence of Cybenetics certification at the time of publication.
Full Specifications
| ASIN | B0FPCH3SY1 |
| Brand | Lian Li |
| Wattage | 1200 watts |
| Fan Count | 1 |
| Model Name | SX1200P.W |
| Form Factor | ATX |
| Item Weight | 7.18 pounds |
| Manufacturer | LIAN LI |
| Connector Type | PCI Express |
| Cooling Method | Air |
| Output Wattage | 1200 Watts |
| Item model number | SX1200P.W |
| Compatible Devices | Computer System, Graphics Card, Motherboard, Processor, Internal Components |
| Product Dimensions | 5.91 x 3.39 x 5.51 inches |
| Item dimensions L x W x H | 5.91 x 3.39 x 5.51 inches |
What Buyers Say
Users are generally positive about this power supply, especially its compact 140mm depth which is a big win for smaller cases. The fanless mode at low loads gets a lot of love for keeping things quiet, and the braided cables are appreciated for making builds look clean. However, some folks have pointed out that the white cables might have a slight off-white tint, but Lian Li offers free replacements if you want pure white.
“Man, this thing is tiny for a 1200W PSU, fits perfectly in my SFF build, but seriously, the 'white' cables are kinda purple, had to hit up Lian Li for real white ones. Still, super quiet.”
Common Praise
- The 140mm depth makes it fit in a wide range of cases, freeing up routing space.
- Fanless operation at loads under 40% keeps the system quiet.
- Flexible braided cables with cable combs make cable management straightforward.
- The 10-year warranty provides long-term confidence.
- Stable power delivery at Platinum efficiency levels.
Common Complaints
- The white cables can have a blue/purple tinge, requiring a replacement request from Lian Li.
- Some reviewers noted the lack of Cybenetics certification at the time of their review.
Ownership Tips
- The fanless mode is genuinely silent during light use, making a noticeable difference in ambient noise.
- The compact size really does make a difference in cable routing, even in standard ATX cases.
- The braided cables feel premium and hold their shape well, aiding in a clean aesthetic.
- The 12V-2x6 connector feels secure and robust for high-power GPUs.
Frequently Asked Questions
Does this PSU come with a 12V-2x6 cable?
Yes, it includes a 12V-2x6 cable, making it compliant with ATX 3.1 and PCIe 5.1 standards for modern graphics cards.
What is the efficiency rating of this power supply?
It is 80 Plus Platinum certified, meaning it achieves up to 92% efficiency at 50% load.
Is the fan always running?
No, it features a fanless mode that keeps the fan off for silent operation when the power supply load is at or below 40%.
What is the warranty period for this PSU?
Lian Li provides a 10-year warranty for this power supply.
Are the cables modular?
Yes, this is a fully modular power supply, allowing you to connect only the cables your system needs.
Buying Guide
When you're looking at power supplies, you're basically buying the heart of your PC. It needs to supply enough wattage for all your components, especially your graphics card and CPU, without breaking a sweat. Efficiency ratings like 80 Plus Platinum tell you how much power it wastes as heat – higher efficiency means less wasted energy and often quieter operation. The form factor and modularity are also key for how easy it is to install and manage cables in your case.
Wattage (1200W)
This is the total power your PSU can deliver. For high-end gaming PCs with powerful graphics cards and CPUs, 1200W ensures you have plenty of headroom for stable operation and future upgrades, preventing system crashes or instability under load.
80 Plus Platinum Certified
This certification means the PSU converts at least 92% of the AC power from your wall into usable DC power for your components at 50% load. It translates to less electricity wasted as heat, lower energy bills, and a cooler, quieter running system.
ATX 3.1 & PCIe 5.1 Compliant
These are the latest standards for power supplies, crucial for compatibility with modern, power-hungry graphics cards that use the new 12V-2x6 power connector. It ensures your PSU can handle the transient power spikes these cards can demand without issues.
140mm Depth
This is the physical length of the power supply. A shorter depth like 140mm is a big deal for smaller PC cases (like ITX or some mATX builds) where space is tight, making installation easier and improving airflow.
Alternatives
If this PSU doesn't fit, look for a lower wattage unit if your components don't demand 1200W, or consider a different form factor like SFX if you need an even smaller physical size.
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