Aorus x370 Gaming K5 + Ryzen 7 1700 no POST, CPU error

[Lewinator56]

after replacing my initial motherboard (MSI b350 tomahawk), with the AX370 gaming k5, im still suffering the 'CPU fail' led lighting up when i try to post. The CPU has been tested working by a 3rd party, all of the other components in the system are either recycled from my old system (apart from the ram) or are new.

When initially tested in the new board, i tested with only the CPU, no RAM, or GPU or HDDs connected, i had a CPU fail when this occurred, a repetition of the issue i had with the b350 board, i did not test with any other components installed after this due to the fact that i had already done that on the b350 board, and had the same issue.

i have a few ideas that could be the cause of the issue:
- MOBO shorting on my case (though my current MOBO does not)
- PSU not supplying power correctly on the 2x4pin connector for the CPU (though, my current system works fine, but does only use one 4pin for the CPU)
- Does POSTing on a UEFI board require there to be at least one stick of RAM to allow the UEFI lo load itself before it can check any components? (i know ram is necessary for a full boot, though, to test hardware such as the CPU i am not sure if RAM is needed, the RAM led did not light without it)

other than the above ideas, i am completely lost, everything should work, the board looks fine, and powers on, it does not turn off after an amount of time, it will just stay on effectively idling with no RGB LEDs on, just the CPU LED on. The PSU should be fine (it happily powers an FX 8350 with no issues), and no MOBOs have ever shorted out in my case before.

Build System:
CPU: AMD Ryzen 7 1700
MOBO: Gigabyte Aorus x370 Gaming K5
GPU: Powercolor PCS+ AMD R9 380 4GB
RAM: 2xcorsair vengeance 8GB LPX DDR4 @2400MHz (on the QVL)
PSU: XFX TS 750W
CASE: NZXT Pahntom

Current (Working) System:
CPU: AMD FX 8350
MOBO: Asus m5a78l-m/usb3
GPU: Powercolor PCS+ R9 380 4GB
RAM: 2xHyperX Fury 8GB @1866MHz + 1xCrucial 8GB (dont know the model) @1600MHz DDR3
PSU: XFX TS 750W
CASE: NZXT Pahantom

any help would be appreciated.... as all of the components seem to be working fine, unless i try to assemble them

 

[DRagor]

So, the new mobo came in, you put CPU into and nothing else, and when CPU LED lit, you decided it's enough of testing and put it all away? I would at least try to make it to minimal build before calling failure (in case of ryzen builds, it's one stick of ram and GPU aside from mobo and CPU). Because right now, you have a CPU that is tested elsewhere to be working, PSU that obviously works, and 2 new motherboards that don't make the trick, so it would mean both motherboards are faulty, which is just unlikely (though not impossible of course).

 

[Lewinator56]

effectively yes, and no, on the first MOBO i tested with a full build (RAM, HDDs, GPU etc....) and had the CPU fail led light, on the second board, i conducted testing as specified by some people, that suggested testing components individually, with only the components being tested in the board to eliminate any other possible errors.

despite teh lack of RAM or a GPU in the second board, only the CPU light was on, not the RAM or VGA LED, unless these will only show after the CPU has passed POST?

 

[DRagor]

You know, the problem with debug LEDs is, they can be misleading. You see CPU led lit and think 'it's CPU problem'. But in fact it could be motherboard problem or even ram problem (as memory controller is in CPU). And CPU alone can't pass POST - it makes no sense to test anything less then minimal build, as any results you get this way can be misleading.

 

[Seanie280672]

Can you try with another PSU ? I know you say its working on another system, but even they have compatibility problems although you wouldnt really expect it, im not 100% sure of this, but im sure I read a while back about issues with XFX PSU's.

Look at it this way, you're on a new board, and the CPU tested fine in another system, so you know thats not really the issue, but maybe a fault with the PSU isnt supplying enough voltage to the CPU itself, hence the CPU debug LED.

 

[Lewinator56]

that could be a possibility, however, the PSU has not given me any problems powering my FX 8350, which is a 125 watt CPU, running on ~1.4v, whereas the R7 1700 is only 65 watts, at ~1.3v, ill see if i can find another PSU to test it with.

the PSU showed no issues back in the working system when i rebuilt it.

 

[Lewinator56]

You know, the problem with debug LEDs is, they can be misleading. You see CPU led lit and think 'it's CPU problem'. But in fact it could be motherboard problem or even ram problem (as memory controller is in CPU). And CPU alone can't pass POST - it makes no sense to test anything less then minimal build, as any results you get this way can be misleading.

I'l test in a minimal build this weekend, and try to find any issues, i guess that makes sense, i forgot that the memory controller is on-chip, should have tested with RAM in the first place.

 

[forgottengao]

Did you resolve the issue? I’m having the exact same issue right now with my AX370 K7 MOBO.

You know, the problem with debug LEDs is, they can be misleading. You see CPU led lit and think 'it's CPU problem'. But in fact it could be motherboard problem or even ram problem (as memory controller is in CPU). And CPU alone can't pass POST - it makes no sense to test anything less then minimal build, as any results you get this way can be misleading.

I'l test in a minimal build this weekend, and try to find any issues, i guess that makes sense, i forgot that the memory controller is on-chip, should have tested with RAM in the first place.

 

[Lewinator56]

Did you resolve the issue? I’m having the exact same issue right now with my AX370 K7 MOBO.

You know, the problem with debug LEDs is, they can be misleading. You see CPU led lit and think 'it's CPU problem'. But in fact it could be motherboard problem or even ram problem (as memory controller is in CPU). And CPU alone can't pass POST - it makes no sense to test anything less then minimal build, as any results you get this way can be misleading.

I'l test in a minimal build this weekend, and try to find any issues, i guess that makes sense, i forgot that the memory controller is on-chip, should have tested with RAM in the first place.

yes, i did resolve the issue, turns out that i just needed to test with the RAM in, considering the design of the RYZEN CPUs, with the memory controller on-chip, if testing with RAM does not work, id recommend checking that your RAM is definitely on the QVL, i had an issue with a b350 board that i replaced where the RAM was on the QVL but did not actually work in the board.