FSP Dagger Pro SFX 850W
Expert rating8.3 / 10
- Wattage:
- 850 W
- 80 PLUS Rating:
- Gold
- Modularity:
- Fully Modular
- ATX Standard:
- ATX 3.1
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Disclaimer: The price and specification of the given product may differ from the actual product. Please confirm on the retailer's website before buying.
Manufacturer: FSP Last updated: 2026-09-12
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FSP Dagger Pro SFX 850W (850W/80+ Gold/Fully Modular/SFX-L/ATX 3.0/Compact High-End Tier) Review
Trying to cram a high-wattage GPU into a compact SFX-L build, the FSP Dagger Pro SFX 850W is one of the few 850W SFX-L units with a native 12V-2x6 connector and full ATX 3.0 spike-handling support.
We'd recommend this specifically for SFF builders pushing an RTX 4080/4090-class card into a small case, since 850W in SFX-L is genuinely hard to find at this efficiency and connector spec. It runs its 92mm fan harder than a full-size ATX unit would at the same load, so expect more noise under sustained gaming.
High Wattage in a Small Footprint
SFX-L is slightly larger than standard SFX, giving FSP room to fit 850W of Gold-rated components with a native ATX 3.0 12V-2x6 connector, something most SFX-L units in this wattage class still lack.
Comparison to Alternatives
Against the ASUS ROG Loki SFX-L 850W Platinum already in the catalog, the Dagger Pro drops to Gold efficiency to hit a lower price at the same wattage and form factor. Against the Lian Li SP750, the Dagger Pro offers 100W more headroom and native ATX 3.0 support, aimed at higher-end SFF builds.
Specifications
Identity
| Brand | FSP |
|---|---|
| Model Number | Dagger Pro 850W |
Output and rails
| +12V Rail Amperage | 70.83 A |
|---|---|
| Single +12V Rail | Yes |
Standards and compliance
| PCIe CEM Standard | PCIe 5.1 |
|---|
GPU power delivery
| Native GPU Cable Incl | Yes |
|---|
Connector inventory
| EPS 8-pin Connectors | 2 |
|---|---|
| SATA Connectors | 6 |
| Molex Connectors | 2 |
Form factor and fit
| Length | 100 mm |
|---|---|
| Colour | Black |
Cooling
| Fan Bearing | Ball |
|---|
Build quality
| Topology | LLC resonant + DC-DC |
|---|---|
| MTBF | 100000 hours |
Cables
| Modularity | Fully Modular |
|---|---|
| Cable Type | Flat Ribbon |
Monitoring, protection and price
| Protections | OCP, OVP, SCP, OPP, OTP |
|---|---|
| Price | 159.99 USD |
| Warranty | 10 years |
| Wattage | 850 W |
|---|---|
| 80 PLUS Rating | Gold |
| ATX Standard | ATX 3.1 |
| Form Factor | SFX |
| Cybenetics Efficiency | Gold |
| Cybenetics Noise | A- |
| 12V-2x6 Connectors | 1 |
| Zero-RPM Mode | Yes |
| Sleeved Cables | No |
| PCIe 8-pin Connectors | 4 |
| Connector Count | 1x 24-pin ATX, 2x EPS 4+4, 1x 12V-2x6, 4x PCIe 6+2-pin, 6x SATA, 2x Molex |
| Fan Size | 92 mm |
| Fan Model / Bearing | 92mm ball bearing |
| OEM / Platform | FSP |
| Japanese Capacitors | Yes |
| Cable Lengths | 24-pin 450mm, EPS 450mm, PCIe 450mm, SATA 450-600mm |
| Source URL | https://www.fsplifestyle.com/us/product/DAGGERPRO850W_GEN5.html |
Expert Review
Reviewed by Burooj Alam. Rated by us, not by users.
Expert rating8.3 / 10
One of the few 850W SFX-L units with native ATX 3.0 support, ideal for high-end small-form-factor builds.
Best for
- SFF builds running RTX 4080/4090-class GPUs
- Buyers wanting native 12V-2x6 in a compact form factor
- SFX-L compatible cases with room for a longer PSU
Not for
- Standard ATX tower builds
- Noise-sensitive quiet builds under sustained load
- Buyers on a tight PSU budget
FAQs
What are the key specifications of the FSP Dagger Pro SFX 850W (850W/80+ Gold/Fully Modular/SFX-L/ATX 3.0/Compact High-End Tier)?
The FSP Dagger Pro SFX 850W (850W/80+ Gold/Fully Modular/SFX-L/ATX 3.0/Compact High-End Tier) is a power supply from FSP. Key specs: Wattage 850 W, 80 PLUS Rating Gold, Cybenetics Efficiency Gold, Cybenetics Noise A-, Modularity Fully Modular.
Will the FSP Dagger Pro SFX 850W (850W/80+ Gold/Fully Modular/SFX-L/ATX 3.0/Compact High-End Tier) work with my current setup?
The FSP Dagger Pro SFX 850W (850W/80+ Gold/Fully Modular/SFX-L/ATX 3.0/Compact High-End Tier) lists Wattage is 850 W. Check that against the hardware you already own before buying, since this is the field that most often decides whether a part fits.
Who is the FSP Dagger Pro SFX 850W (850W/80+ Gold/Fully Modular/SFX-L/ATX 3.0/Compact High-End Tier) best suited to?
It suits sff builds running rtx 4080/4090-class gpus, buyers wanting native 12v-2x6 in a compact form factor, sfx-l compatible cases with room for a longer psu.
What are the drawbacks of the FSP Dagger Pro SFX 850W (850W/80+ Gold/Fully Modular/SFX-L/ATX 3.0/Compact High-End Tier)?
It is a poor fit for standard atx tower builds, noise-sensitive quiet builds under sustained load, buyers on a tight psu budget.
Compare and read more
- ASUS ROG Loki SFX-L 1000W Platinum (1000W/80+ Platinum/SFX-L/Fully Modular/ATX 3.0) vs FSP Dagger Pro SFX 850W (850W/80+ Gold/Fully Modular/SFX-L/ATX 3.0/Compact High-End Tier)
- ASUS ROG Loki SFX-L 850W Platinum (850W/80+ Platinum/ATX 3.0/Popular High-End Gaming Tier) vs FSP Dagger Pro SFX 850W (850W/80+ Gold/Fully Modular/SFX-L/ATX 3.0/Compact High-End Tier)
- ASUS ROG Loki SFX-L 750W Platinum (750W/80+ Platinum/SFX-L/Fully Modular/ATX 3.0) vs FSP Dagger Pro SFX 850W (850W/80+ Gold/Fully Modular/SFX-L/ATX 3.0/Compact High-End Tier)
- ASUS ROG Thor 1000W Platinum II (1000W/80+ Platinum/Fully Modular/OLED Display/0dB Mode) vs FSP Dagger Pro SFX 850W (850W/80+ Gold/Fully Modular/SFX-L/ATX 3.0/Compact High-End Tier)