SilverStone Releases Its First Flex ATX Power Supply

Flex ATX power supplies (PSUs) are notably smaller than standard ATX PSUs, so they are mostly used in small chassis hosting Flex ATX or Mini ITX motherboards or in rackmount servers with limited height, such as 1U racks. SilverStone is a pioneer when it comes to high power density PSUs, and with the introduction of the FX350-G, the company now has a contender in the Flex ATX category.

Thanks to its super compact dimensions and 350W output, this unit achieves a pretty high power density score, reaching 707 Watts per liter. Moreover, it is able to deliver full load continuously (24/7) at up to 40℃ operating temperatures, while it is 80 PLUS Gold certified. There is no Cybenetics certification, though, so we don't have any data on its noise output. Given the PSU's compact dimension and the small, 40mm fan, we don't have high hopes for silent operation. SilverStone mentions a 20 dB(A) figure, but this only represents the PSU's minimum noise output, and there is nothing about maximum operating noise. When you see brands avoiding to provide a fan speed or a fan noise/speed graph, then surely there is something going on.

The amount of provided cables is low, since Flex ATX PSUs are mostly used in special purpose machines and not in gaming or server stations. So besides the absolutely necessary connectors (24-pin ATX and EPS), we find a single PCIe, three SATA, two 4-pin Molex, and a berg connector. All cables are native and, thankfully, sleeved. They consist of normal, colored gauges though and not stealth ones. Finally, despite the PSU's super compact dimensions, SilverStone still found the necessary space to install a power switch.

We don't have any availability date for the U.S. market but we do have a clue about the FX350-G's price, which most likely will be around $100-$105. Lastly, we cannot know the OEM unless we tear down the PSU or we have some solid information to rely on.

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SilverStone Flex ATX Features & Specs
OEMno info
Efficiency80 PLUS Gold
NoiseNo Cybenetics Rating
C6/C7 Sleep States CompatibleYes
Operating temperature0°C - 40°C
ProtectionsOver Voltage Protection Over Power Protection Short Circuit Protection
Cooling40mm Fan
Semi-Passive ModeNo
Dimensions (W x H x D)81.5 x 40.5 x 150mm 3.21 x 1.59 x 5.91"
Form FactorFlex ATX
ComplianceATX12V v2.4
Connectors1 x 24 / 20-Pin motherboard connectorï¼350mmï¼ 1 x 8 / 4-Pin EPS / ATX 12V connectorï¼450mmï¼ 1 x 6-Pin PCIe connectorï¼350mmï¼ 3 x SATA connectorï¼350mm / 150mm / 150mmï¼ 2 x 4-Pin Peripheral connectorï¼350mm / 150mmï¼ 1 x 4-Pin Floppy adapter connectorï¼350mm / 150mm / 150mmï¼
+12V Max Power350W
5V & 3.3V Max Power90W
Warranty3 years
MSRPApproximately $105
Contributing Editor

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.