Question Seasonic Focus Plus Gold and 8+4 CPU Connectors

[JBHapgood]

I will be building a system around the new AMD Ryzen 3600 CPU. While I'd prefer a B450 motherboard, many of them are having BIOS problems. So I'm also looking at low-end X570 motherboards.

The X570 boards that look most promising are the MSI X570-A PRO and MPG X570 Gaming Plus. They're apparently identical, except the latter has "gaming aesthetics" and a larger heat sink. Both have 8+4 CPU power connectors.

I'm planning to get a Seasonic Focus Plus Gold PSU. All the PSU calculators agree that the 550-watt version should be more than adequate for any motherboard I choose. I'll be running the 3600 at stock speed with the stock cooler, with a Gigabyte Nvidia GTX 1050 video card (I don't game or edit video, so anything more powerful would be a waste of money). But the 550-watt PSU only has the 8-pin CPU power connector. The 750-watt version does include another CPU power connector for the second 4-pin socket on the motherboard.

I've read numerous forum posts insisting that the second 4-pin connector is necessary only for overclocking high-power CPUs. But I've also seen a few posts stating that some motherboards have stability problems or refuse to boot if that second socket isn't connected, even if it shouldn't be necessary. The manuals for the the MSI X570 motherboards shed no light on this question, and only specify connecting all 12 pins.

The 750-watt version would surely be overkill. But it turns off its fan when lightly loaded, and it occurred to me that the 750-watt version would effectively give me a fanless PSU at a lower cost than a decent true fanless PSU.

Advice please?

 

[geofelt]

I really doubt that your psu is the problem.
A bad motherboard is much more likely if you are thinking a hardware defect.

Look elsewhere for your problem.

In addition to flipping the power switch, you also need to start the motherboard.
If there is a start button on the motherboard, use that.
Otherwise you need to momentarily short the two PWR pins on the front panel header.

I would expect to see nothing unless the cpu and ram were also installed.

 

[TJ Hooker]

FYI, in the future if nothing happens when you press the power button it may be a good idea to verify if the PSU starts up on its own (not connected to any of your other components) using the paper clip test. http://support.antec.com/support/so...19-is-my-power-supply-dead-the-paperclip-test

 

[JBHapgood]

I must apologize for needlessly impugning the reputation of Antec and Seasonic.

This morning I woke up at 6AM to an epiphany: The PSU did nothing when I switched it on because I had neglected to press the Power button on the front of the computer! You can either condemn me as a stupid idiot with oatmeal (or worse) for brains, or forgive me for being so focused on the back of the computer that I completely forgot about the front.

Either way, I got out of bed, went to my computer room, plugged in the power cord, monitor, and keyboard, switched on my UPS and the PSU, and then pressed the Power button. The motherboard went through its POST sequence, turned on its LEDs in sequence, and brought up the BIOS. I then adjusted the RAM speed timing, booted the thumb drive containing MemTest, and successfully ran four passes of the test suite, which took about three hours. Then I installed Windows, and I'm writing this.

So if anyone else installs a power supply, wires up all the cables, switches it on, and nothing happens, remember to press the Power button!

 

[Karadjgne]

Lol. It's amazing how often ppl overlook some of the most obvious things.

 

[geofelt]