Underpowered SATA power?

[Madellyn]

I’m currently rebuilding a new computer with a mix of old and new parts. I’m repurposing the CoolerMaster V series 850 watt power supply from my old computer for this build because it’s been solid for around a year. On paper 850 watts should be more than enough for this build but in practice I think I may be overloading the SATA power provision. I have all four power cables plugged in with three to four devices on each cable. I have four HDDs, three SSDs, an AIO for my CPU, a fan controller and two SATA power connectors hooked up to a pair of USB controllers.

 

Whenever I boot up, a random assortment of the drives show up in BIOS and the one time I got them all to show up then the USB controllers were acting funny with USB devices constantly dropping and out especially when they started using more power or bandwidth. Unplugging the USB controllers from the power made more drives show up in bios. At this point I’m resigned to needing a new power supply but I’m not sure what to look for to ensure that I can actually power what I have. 

[--SID--]

850w is more than enough, it's the 5V line that's limited. Both SATA and USB devices use 5V. You need a PSU that can deliver more power at 5V.

[Madellyn]

That makes sense and I’m glad to hear someone else thinking it’s a power problem too. The current supply only has 20A on the 5V line but looking at others I can only see up to 25A for sale. I’ve ordered something with 25A and undervolt protection so we’ll see how I go with that. The common advice I kept seeing was that you shouldn’t need to worry about the lower lines like 5V and 3.3V though.