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FSP Mini ITX Solution/Flex ATX 300W Fully Modular Cable Management Efficiency =90% Full Range Active PFC Power Supply (FSP300-57FCB)

Ships from United States. Most customers receive within 3-7 days.

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  • Compliant with the latest Flex ATX V1.22
  • 300W: Efficiency = 85% at typical load 80 PLUS GOLD Certified
  • Compliant with UL/EN/IEC 62368-1 and 60950 International safety standards
  • Complete protections: OCP, OVP, SCP, OPP, OTP
  • Main Japanese electrolytic capacitors | Power cord not included

  • Overview
  • Specifications
  • Warranty & Returns
  • Reviews
FSP Group FSP Group
FSP Group

Fully Modular Design

Fully modular design with all black ribbon cables simplifies installation, which allows you to use only the cables you need, for a much neater build.

FSP Group

High Power Density

Flexguru series featured with high power density, 20% higher than any Flex PSU in the same wattage and frame.

FSP Group

Firm Installation with Flexible Bracket Design

FSP pioneered the development of the bracket design in FLEX-ATX PSU, and we applied it on the FlexGuru series. The new design strengthens the fixation adequacy which makes the PSU fit in most of the Flex-ATX chassis in the market.

FSP Group

Excellent Thermal Performance

Differ from the genernal FLEX PSU, FlexGuru series is designed with inner 40mm fan, noise cancellation and achieving maximum cooling at all times.

FSP Group

90% Efficiency Conversion

The efficiency of your power supply directly affects your system’s performance. FlexGuru 300W has a guaranteed typical efficiency of 90%, offer the high conversion power to boost your system.

FSP Group

Application Field

FSP Group

Keep in Compliance IEC 62368

FSP Group brings you the latest technologies in renewable energy, they provide a full range of additional safety features to keep up with the latest regulations. FSP has upgraded the majority of their power supplies to the latest UL# 62368 standard.

FSP Group

Safety Protection

OVP (Over Voltage Protection), UVP (Under Voltage Protection), OPP (Over Power Protection), SCP (Short Circuit Protection), and OTP (Over Temperature Protection), a full guardian circuit protections to keep your hardware safe.

100% Japanese Electrolytic Capacitors

Using Japanese electrolytic capacitors, Flexguru series offers a stable output and long-term reliability you need.


FSP Group


FSP Group


FSP Group


Model FSP300-57FCB
Rated Output Power 300W
Form Factor FLEX ATX
Input Voltage 100-240V
Input Current 6-3A
Input Frequency 60-50Hz
PFC Active PFC
Efficiency 90%
Fan Type Ball Bearing, 40mm
Dimensions(L x W x H) 150 x 40.5 x 81.5mm
Operation Temp. 100,000 Hrs
Protection UVP, OVP, SCP, OPP, OTP

Learn more about the FSP Group FSP300-50FGBBI(M)

Warranty, Returns, And Additional Information
  • Warranty
  • Limited Warranty period (parts): 2 years
  • Limited Warranty period (labor): 2 years
  • Read full details
Ownership: 1 month to 1 year
Verified Owner
4/ 5
Not what I expected, still good though. 2/13/2020 9:29:34 AM

Pros: Powers my R7 2700 and GTX1050Ti without problem.
Mostly Black.
80P Gold.

Cons: PCB is green not tan like the pictures.
Fan could be quieter, and there are quieter 40x15mm fans out there.

Overall Review: Great psu if you need this form factor.

It doesn't make sense to have black body and cables/connectors, with a green pcb, because it makes it seem like it is aimed towards aesthetics but it is not at the same time. Plus there is a goop of white stuff probably some non-conductive material meant to aid in preventing things from shorting out, but still... it looks gross. If you need this form factor psu and have similar to less hardware than I do, I recommend it. Same if you are a sff pc builder but then you already know you have some work to do. Good product, even if it doesn't know what it is trying to be, I like it. Thank you FSP Group. Fan is 40x40x15mm fyi

2 out of 2 people found this review helpful. Did you?
Ownership: 1 week to 1 month
Verified Owner
5/ 5
A very compact Flex! 2/3/2020 6:42:02 AM

Pros: Small / modular for tiny ITX cases. (put mine in a Velka 3)
Quiet (no fan noise for me so far, see specs of machine below)

Cons: Fan is VERY loud at maximum speed. It never gets to this speed during normal use, but I don't see why FLEX ATX power supplies need to be designed this way.

Overall Review: Installed in a Velka 3 with a i7 9700k and a quadro p1000. been using it for CAD, halo reach and CIV 6. I haven't heard the fan yet. The flat cables are great for jamming into this tiny case, and you don't have to have the sata / molex cables in there at all if you're going with m.2 ssd. It's pretty great so far!

3 out of 3 people found this review helpful. Did you?
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