Aorus Master x570 usb voltage issues

Hello, I would appreciate some thoughts on the following issue! I’m 99.9% sure it started after upgrading my 3800x to 5900x, all other components remained the same. Error logs shows the problems starting within 12 hours of the CPU upgrade. Using Linux if this makes any difference.

Some days ago I noticed that an external USB HDD was clicking off and on at random. Initially I thought the drive was simply failing but after spending some time troubleshooting this today I noticed that 5v voltage reported in bios was at 4.6v. I brought out my multi meter to check PSU voltage and it remains steady at 5.02v, despite what the bios says (so I assumed bad reporting).

I also decided to check voltage in the USB ports and noticed that the port that the external HDD is connected to actually is at 4.6-4.8 volts! So I decided to measure the rest of the ports and getting the same 4.6-4.8 on all ports on the back plane. The voltage on the internal motherboard USB header connected to front of the case however is showing very steady 5.329v!! All this while PSU 5v rail is steady at 5.02v… what is going on here??

I also have a USB 3.0 add-in card where both ports are steady at 5.02v. 12v is at 12.05v and 3.3v is at 3.31v measured by multi-meter. Bios shows 11.8v and 3.2v. Power supply is a Corsair AX860i (supposedly one of those manufactured by Seasonic, as that’s why I got it, but I might be wrong).

The initial problem with the external USB HDD was also solved by moving it to another PC.

Motherboard bios is latest (F33).

Anyone has any ideas? Motherboard issue? Firmware issues?

edit: I should probably add that I made all voltage measurements with all USB devices disconnected. Having the USB devices connected or not made no difference though.

I’m still trying to narrow this down to either the motherboard or the PSU. Anyone can chime in? I’m out of warranty and got no spare parts to test with and want to avoid buying the wrong replacement. :grimacing:

Since last post I’ve done some more voltage measurements:

Motherboard USB headers are all ~4.6-4.8V except on one of the USB3 front connectors which shows ~5.3V very steadily. Looking at the board this one seems to have it’s own voltage regulators. This makes me believe that other 5V voltage regulators on the motherboard for USB and possible other things are failing. I should add that I’m not sure motherboards even have 5V voltage regulators, I thought 5V was solely regulated by the PSU, so I might be wrong…

The motherboard in bios reports ~4.6-4.8V. HWMonitor reports the same. Measuring 5V in back plate USB ports i see the same 4.6-4.8V. I didnt find any 5V measuring point on the motherboard itself to check this.

Since the PSU is a Corsair with iCue I booted up windows to check it’s values and they’re all good at 5.02V, 12.1V and 3.31V. Further measurements with multimeter ATX24 connector 5V: 5.02V 5VSB: 5.02v 12V: 12.05V. So the PSU seems to be in good shape.

The problematic USB ports start out at 4.8V with nothing connected and pretty quickly drops down to 4.6V with a few devices connected. With my limited electrical knowledge this really points to bad regulators or caps.

So is the motherboard really at fault here?

Do you have one of those USB-Multimeters to check for Voltage (and Current) under load?

It may be that the motherboard generates 5V for some headers from the 12V rail while others run of the PSU. One capacitor or feedback resistor being bad could cause the strangest voltages to show up.

You’ll have I²R losses over long cables. Try plugging the drive in with a 15cm cable if you’re using a 1M, 1.5M cable.

To borrow from Mark Twain, I don’t know the answer but I sure admire the question. But while I don’t know, I am thinking motherboard (possibly firmware).

Sounds like you’ve done a good, thorough job of voltage measurements. There is ample evidence online that USB power is not directly wired to the PSU, but “managed” by the motherboard. Combined with your observations, this makes a good case (but surprising!) that the issue is motherboard-related.

The link with the CPU change could be coincidence, but raises concern about a firmware issue or possibly a weakness with the Aorus Master X570 (all of them). So you might think twice about replacing with the exact same model.

If you still have the 3800x CPU, and can endure the effort, you might try putting that CPU back in and see whether the issue clears up. Either way, it wouldn’t give a complete answer, but would add an interesting fact. I suppose if the 3800x works fine, it might suggest that this particular motherboard has always been marginal but barely okay with the first CPU.

If I were you, I would consider “limping along” by using a good USB port, perhaps on the add-in card, and adding a USB hub. Just something to consider.

Good luck finding a resolution or workaround.

I think you should try to narrow down if the problematic USB ports belong to the chipset or the CPU. If they belong to the chipset it might be a motherboard issue that cropped out of nowhere, maybe due to the new BIOS. If they’re connected to the CPU, you might have a defective CPU that’s signaling too low of a voltage for the USB ports.

Thank you all for the replies.

In the end it was the power supply. The old PSU (AX860i) did measure proper 5v on all of its outputs even under load, so I’m confused as to what was going on.

A couple of hours after the CPU upgrade I remember hearing a muffled pop from inside the case. It was an unusual sound but I brushed it off as one of the HDDs acting up. As I removed the old PSU however I hear something rattling inside it and guess what? It seems to be a piece of a capacitor!! I couldn’t get it out and I don’t want to break the warranty void seals just yet since I think corsair have 10 year warranty on all their AX line up, so I’m going to hopefully get it replaced.

I probably failed to measure the old PSU properly, but I’m happy at least it wasn’t the motherboard!

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