be quiet! Straight Power 11 Platinum 1000W Quiet Performance Power Supply | Fully Modular | BN644
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AI Verdict
This is an ultra-quiet, highly efficient 1000W ATX power supply built for noise-obsessed PC builders who don't mind manually balancing PCIe cables across multiple 12V rails.
The acoustic performance is unmatched thanks to the Silent Wings 3 fan, but the ATX 2.51 standard and multi-rail design make it clunky for modern builds. You have to use adapters for newer GPUs and carefully balance the 12V rails to avoid tripping the over-current protection.
If you are buying an RTX 40-series or 50-series GPU, look for an ATX 3.0 power supply with a native 12VHPWR port to avoid adapter clutter.
Regret Score™
Very Low RiskLower is better — measures purchase-regret risk from real buyer complaints, review credibility, and product maturity
Issues discovered after purchase
Critically weak dimension
Amazon rating vs actual quality
Chance this product isn't for you
Pros
- Silent Wings 3 135mm fan stays under 230 RPM until you hit a 500W load
- 80 PLUS Platinum certified, hitting up to 94.1% efficiency at 50% load
- Wire-free internal DC side design improves airflow and reduces signal interference
- Includes six PCIe 6+2 pin connectors for multi-GPU or high-draw setups
- Compact 170mm length fits easily into most mid-tower ATX cases
Cons
- Only includes a 5-year warranty, falling short of the 10-year standard for flagship units
- Multi-rail 12V design requires you to read the manual to balance GPU power loads
- Cables are bundled in stiff nylon mesh rather than being individually sleeved
- ATX 2.51 standard means no native 12VHPWR cable for RTX 40-series cards out of the box
Dimension Scores
80 PLUS Platinum hitting 94.1% efficiency with clean DC-to-DC voltage regulation.
The 135mm Silent Wings 3 fan peaks at just 28.1 dB(A) under 100% load.
Internal wire-free design and Japanese 105°C capacitors are top-tier, but the 5-year warranty docks points.
Fully modular, but the nylon-sleeved cables are stiff and the multi-rail layout complicates routing.
Best For
- Audio producers or streamers needing a dead-silent studio PC
- High-end gaming rigs with older ATX 2.0 GPUs like the RTX 3080 or RX 6900 XT
- Mid-tower builds where a 170mm PSU length leaves room for cable management
Not Recommended For
- First-time builders who might plug all GPU cables into the same 12V rail
- RTX 4090 owners who want a native ATX 3.0 12VHPWR connection without adapters
Watch Out For
- Multi-rail load balancing is mandatory — if you plug a high-draw GPU into rails 1 and 2 instead of 1 and 3, you will experience severe coil whine or system shutdowns.
- The included cables use thick nylon mesh sleeves with heat shrink at the ends, making them incredibly stiff and hard to bend in tight cases.
- You only get a 5-year warranty, which is half the lifespan guaranteed by similarly spec'd 1000W Platinum units from other brands.
Full Specifications
| ASIN | B085WW32T2 |
| Brand | be quiet! |
| Color | Black |
| Series | straight power 11 |
| Wattage | 1000 watts |
| Model Name | straight power 11 |
| Form Factor | ATX |
| Item Weight | 8.8 pounds |
| Manufacturer | be quiet! |
| Connector Type | PCI Express |
| Cooling Method | Air |
| Output Wattage | 1000 Watts |
| Item model number | BN644 |
| Compatible Devices | Personal Computer |
| Product Dimensions | 13 x 9.75 x 4 inches |
| Item Dimensions LxWxH | 13 x 9.75 x 4 inches |
| Item dimensions L x W x H | 13 x 9.75 x 4 inches |
What Buyers Say
The acoustic performance is the absolute star of the show here, with buyers repeatedly praising how the 135mm fan stays dead silent even under heavy gaming loads. The biggest headache reported by users is the multi-rail 12V design, which strictly requires you to balance your GPU cables across specific ports to avoid tripping the OCP. Many users who experienced coil whine or random shutdowns realized they had plugged their PCIe cables into the wrong rails. The stiff, nylon-meshed cables also drew frustration from builders working in compact cases.
“Dead silent and runs super cool, but I spent three days troubleshooting random shutdowns before realizing I had to split my 3090's power cables across rails 1 and 3.”
Common Praise
- Fan noise is completely imperceptible over standard case fans
- Platinum efficiency noticeably reduces heat output into the room
- 170mm length easily clears the hard drive cages in standard mid-towers
- Internal build quality and wire-free DC design feel incredibly premium
Common Complaints
- 5-year warranty feels cheap for a flagship-tier power supply
- Thick heat shrink on the cable ends makes them hard to bend near the motherboard
- Confusing multi-rail layout causes system crashes if you don't read the manual
- Requires buying a separate cable for native RTX 40-series support
Ownership Tips
- The fan never stops spinning, but it stays at 230 RPM for basic desktop tasks and is completely inaudible.
- If you hear a high-pitched squeal under load, check your PCIe cable routing before assuming the unit is defective.
- The flat SATA cables are much easier to route behind the motherboard tray than the bulky 24-pin and PCIe cables.
Frequently Asked Questions
Does this PSU have a zero RPM fan mode?
No, the fan never completely stops. It spins at a virtually inaudible 230 RPM until the system draws over 500 watts.
Will this work with an RTX 4090?
Yes, but you have to use the Nvidia adapter squid or buy a separate 12VHPWR cable from be quiet!. It does not come with a native ATX 3.0 cable.
Why is my PC shutting down during heavy gaming?
You likely tripped the Over Current Protection (OCP). This is a multi-rail PSU, so you must distribute your PCIe cables across rails 1 and 3, not just 1 and 2.
Are the cables individually sleeved?
No. The cables are standard black wires bundled together inside a thick nylon mesh sleeve with heat shrink at the ends.
Does it suffer from coil whine?
The unit itself is highly rated for lacking coil whine, but improper cable routing on the 12V rails can induce high-frequency noise under load.
Buying Guide
When buying a 1000W power supply, you are paying for headroom and silence. This specific unit uses a multi-rail design, meaning the total power is split into four separate lanes rather than one massive pool. You absolutely must read the manual to see which ports to plug your graphics card into, or your PC will shut down during games. Keep in mind this is an older ATX 2.51 unit, so it lacks the single 16-pin cable required by modern Nvidia GPUs.
Multi-Rail 12V Design
Instead of one giant circuit breaker for your whole house, it's like having separate breakers for different rooms. You have to plug your heavy appliances (GPU cables) into different rooms to avoid tripping the system.
80 PLUS Platinum
This is the efficiency rating. It means the power supply wastes very little electricity as heat, which keeps your room cooler and allows the internal fan to spin slower.
135mm Fluid Dynamic Bearing Fan
Larger fans can push the same amount of air as smaller fans while spinning much slower. Slower spinning means less motor whine and less air turbulence noise.
Alternatives
If you want a simpler plug-and-play experience without balancing rails, look for a single-rail ATX 3.0 power supply with a 10-year warranty and a native 12VHPWR cable.
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