Hey everyone,

I wasn't able to find any low load tests for this PSU before I bought it, so I thought this post could be useful for anyone thinking about getting the HDPlex 250W GaN PSU. To help with this, I compared it to the Be Quiet! Pure Power 13 M 550W, which is already recognized as a reliable option for power efficiency. You can find a test review for the latter here. The most interesting figure related to low load efficiency is this one:

Obviously, it reveals that the Be Quiet PSU has an efficiency of 69.6% at 10W load and 77% at 15W load. As I don't have professional measuring equipment, I simply compared the low power loads for a time span of 10 minutes starting 20 minutes after booting. Both PSUs used the exact same hardware, that is:

• Unraid 7.2.2

• Mainboard: Gigabyte C246M-WU4

• CPU: Intel i3 9100

• Memory: 2x 32GB Kingston DDR4-3200 ECC RAM

• Cachedrive: 1x WD Black SN850x NVME M.2 SSD

• No hard drives!

• no running docker containers

• no active case fans, only the CPU fan was running at 400rpm

• the system reaches C10 state

The results look like this (measured with Fritz!DECT 200):

The HDPlex consumes approximately 2,2 W less on average in my idle scenario. Utilizing the same hardware as previously mentioned, along with the HDPlex PSU, my hard drives (5x Toshiba MG08 16 TB SATA HDD, 3x WD WDC161 Gold 16 TB SATA HDD), and running Docker containers, I achieve around 12.8W load during idle when all hard drives are spun down. This is an impressive outcome, IMO.

Plus, I can confirm that the HDPlex PSU can power my eight (!) hard drives without any problems if you don't need the PCI-E power port on the PSU. Four drives are powered by the power cable connected to the SATA power port on the PSU and the remaining four drives are powered by a second custom cable that uses the orange pins in the below figure. The +5V is splitted from the SATA power port, which is no problem since the PSU is a single rail one.

Edited December 19, 2025Dec 19 by Heisenberg7
Mentioned that the PSU is capable of powering eight hard drives

wooow, awesome results, thank you!

Is HDPlex power supply quiet? Do you hear any coil whine sound under some specific load ?

On 12/18/2025 at 5:42 PM, bagican said:

wooow, awesome results, thank you!

Is HDPlex power supply quiet? Do you hear any coil whine sound under some specific load ?

Yeah, the HDPlex is totally passive and thus 100% silent. I haven't heard any coil whine sounds at all so far.

On 12/13/2025 at 5:48 PM, Heisenberg7 said:

Plus, I can confirm that the HDPlex PSU can power my eight (!) hard drives without any problems if you don't need the PCI-E power port on the PSU. Four drives are powered by the power cable connected to the SATA power port on the PSU and the remaining four drives are powered by a second custom cable that uses the orange pins in the below figure. The +5V is splitted from the SATA power port, which is no problem since the PSU is a single rail one.

Hey,

Could I ask you where you got that custom cable and how it’s all wired up? I am trying to do the same thing with 6 drives currently and I am at a loss.

Thanks in advance!

On 3/29/2026 at 8:34 PM, Chalkline said:

Hey,

Could I ask you where you got that custom cable and how it’s all wired up? I am trying to do the same thing with 6 drives currently and I am at a loss.

Thanks in advance!

The cable is self-made, but it is no rocket science. The backplane inside my case utilizes two female 4-pin Molex connectors to supply power to all eight hard drives. I have the following cables to power the hard drives:

1. Cable: 4pin SATA ATX connector to FAT4 male "Molex" connector

2. Cable: 8pin PCI-E ATX connector to FAT4 male "Molex" connector

The wiring is straightforward and illustrated in the figure mentioned earlier. All the orange pins (1, 2, 3, 4) are designated for the second cable. The unique aspect here is that the +5V (orange pin 1) from the first cable is split, ensuring that both cables receive a +5V, as a FAT4 male "Molex" connector requires one +5V, one +12V, and two GND lines. A picture of the cable is included in the attachments. Hope this helps!

Hope I’m not resurrecting, but how’s your experience otherwise? I hope this thing has been rock solid. I have rock solid seasonic bronze psu and many backups of the same psu, but tempted by this thing. Haha.