PC Won't Boot Unless PSU Power Cycled

[ChrisBox]

I built a new PC a few days ago and am now having issues powering it on. I have read the sticky at the top of this forum section and have checked/tried everything that doesn't involve ripping my PC apart. Going to do that if necessary when my next day off is. Hoping someone can provide insight before having to do all of that.

Mobo: ASUS ROG STRIX Z270H Gaming (latest BIOS and drivers)
CPU: Intel i5 7600K (4.8GHz @ 1.3V, cache ratio set to 4.5GHz)
CPU Cooler: Corsair H100i v2 (with stock SP120L fans)
RAM: 16GB Corsair Vengeance LPX DDR4 3000MHz
GPU: ASUS STRIX 980 (1350MHz GPU clock, 1900MHz memory clock, +10mV, 125% power target)
Power Supply: EVGA Supernova G2 650W Modular
OS: Windows 10 Home 64 Bit (both nVidia and Windows power options set to Maximum Performance)

So I built the system 3 days ago. Everything went smoothly. System powers up fine. I'm able to install Windows 10, update BIOS, drivers, etc.

First thing I do is manually overclock to 4.8GHz, set the Vcore to 1.3V and cache ratio to 4.5GHz. PC takes it fine. I stress test with Realbench for 4 hours. Temps are all very good.

Then I decide to play with RAM timings. I use XMP profile (thinking it only affected RAM), so that my RAM speed and timings would be proper. Then I lower the RAMs primary timings by one integer. Afterwards I run a few successful passes in Memtest86.

I go to reboot the PC and it does not turn on. The only indications of power is the RGB strip that is built into the case lights up, and the fans on my graphics card start spinning. Case fans, radiator fans, and radiator pump do not activate. Nothing displayed on the screen, no errors, BIOS, splash screen, nothing.

I panic. Try a few more times, same thing. I then flip the power supply off and back on again, and it starts up fine. I test this a few more times and get the same result (will not boot after shutdown unless I turn the power supply off and then back on again). Also I tested several times the fact that I cannot simply flip the power supply off and on again quickly, that won't work. I need to turn it off, wait 5-10 seconds until all lights on the motherboard turn off, then back to on. That's the only way it will work.

So after turning the power supply off and on, then being able to boot into BIOS, I hit F5 and restore everything to defaults. After this the PC boots fine (tested multiple times).

I assume that the XMP profile or adjusting the RAM timings must have caused some issue, so I decide to leave the RAM alone from now on.

I reapply my manual CPU overclock, and manually set DRAM frequency to 3000MHz, being sure not to load any XMP profile and not to touch any RAM timings. PC boots fine now, multiple times. I run another 4 hour Realbench test and again everything looks good.

I game on the PC for a few hours, run a bunch of benchmarks to compare to the ones I took before overclocking and to results from my previous PC. All good.

Now I move on to overclocking my graphics card. Using MSI Afterburner I set my GPU clock to 1350MHz, memory clock to 1900MHz, add a 10mV offset to voltage, set the power target to 125% and keep the default auto fan speed. Run 2 hours each in Furmark and MSI Kombustor, along with a bunch of benchmarks. Stable, no glitches and temps are all fine.

Over the next 24 hours I do a bunch more gaming, with numerous shut down and restarts in between (I'm that guy who turns his PC off if he isn't using it). No issues.

Until a few hours ago... I go to turn the PC back on and again same as before it will not start, post, boot, give me a splash screen, or activate anything other than the built in RGB and graphics card fans. Fuck...

Again, turning the power supply off, waiting for lights to go off on motherboard, and on again allows me to boot.

I take off my GPU overclock, no change.

On a whim I call ASUS motherboard support and talk to one of their guys. I explain my situation and he is convinced that my 650W power supply isn't sufficient for overclocking, even going so far as to say that overclocking my 7600K to 4.8GHz can cause my CPU to use up to 300W of power alone... not sure where he is getting that from.

I am persistent in asking him to at least consider the motherboard being the issue while being careful not to be biased myself, being open to other possibilities. Nope, he's sticking to that. After some convincing he opens a ticket with "the engineering department" and I should hear from them at some point.

And that's where I'm at. Even with all of the overclocks on, as long as I cycle the power supply I can boot just fine into Windows and run stress tests and game to my hearts content, but once I shut down I'm faced with the same issue until I cycle the power supply again.

Sorry for the novel but I wanted to include as much detail as I could.

Any ideas?

[Windows7ge]

That tech support guy's argument seems invalid to me. If the PSU was insufficient you would have had your computer shutting down mid stability test or the moment you started it. Also for a CPU to use 300W of actual power I think would kill it. The motherboards highest power rail is 12V. In order to come up with 300W it would require 25Amps if the efficiency was 100% which it's not means the load on the PSU would be even higher (by a little bit). Even if the GPU also used 300W of actual power it'd put you at a total of 50Amps. I guarantee you between the +5V and +3.3V handling some of the load and how I very much doubt the CPU is using 300W not even the GPU but the GPU would be closer to it. Even if the guy was right (I'm pretty damn sure he's an idiot) the PSU can STILL deliver enough amps to compensate.

 

My gut tells me it has something to do with the RAM. When the RAM has an odd value (Something other than 2133/2400/2666/2933/3200/etc) depending on the motherboard XMP will adjust the FSB to compensate and without proper voltage control and FSB/RAM ratio it can make the system unstable. You said you already reset the BIOS but I'd try it again. Manually set the memory to 2933MHz or whatever closer option is available, set the primary timing and voltage manually then see how the system behaves.

[ChrisBox]

10 hours ago, Windows7ge said:

That tech support guy's argument seems invalid to me. If the PSU was insufficient you would have had your computer shutting down mid stability test or the moment you started it. Also for a CPU to use 300W of actual power I think would kill it. The motherboards highest power rail is 12V. In order to come up with 300W it would require 25Amps if the efficiency was 100% which it's not means the load on the PSU would be even higher (by a little bit). Even if the GPU also used 300W of actual power it'd put you at a total of 50Amps. I guarantee you between the +5V and +3.3V handling some of the load and how I very much doubt the CPU is using 300W not even the GPU but the GPU would be closer to it. Even if the guy was right (I'm pretty damn sure he's an idiot) the PSU can STILL deliver enough amps to compensate.

 

My gut tells me it has something to do with the RAM. When the RAM has an odd value (Something other than 2133/2400/2666/2933/3200/etc) depending on the motherboard XMP will adjust the FSB to compensate and without proper voltage control and FSB/RAM ratio it can make the system unstable. You said you already reset the BIOS but I'd try it again. Manually set the memory to 2933MHz or whatever closer option is available, set the primary timing and voltage manually then see how the system behaves.

Yeah I pretty much brushed aside the ASUS guys claim that it was a power supply issue the second he said the CPU is drawing 300W when overclocked.

 

I took your advice and investigated RAM further, I think you're right. The system boots fine at 2933MHz!

 

I tried 1.4V (advertised 3000MHz @ 1.35V) on DRAM and adding 0.05V on System Agent and it still will not boot in 3000MHz unless I power cycle the power supply.

[Windows7ge]

2 hours ago, ChrisBox said:

Yeah I pretty much brushed aside the ASUS guys claim that it was a power supply issue the second he said the CPU is drawing 300W when overclocked.

 

I took your advice and investigated RAM further, I think you're right. The system boots fine at 2933MHz!

 

I tried 1.4V (advertised 3000MHz @ 1.35V) on DRAM and adding 0.05V on System Agent and it still will not boot in 3000MHz unless I power cycle the power supply.

RAM because its speed is doubled typically gives you options in 266MHz intervals as I previously exampled. To go to 3000MHz would be an additional 66MHz and to set it at such might maybe (don't quote me on this) put the RAM out of sync with the rest of the system causing issues. I've seen computers overclocking the FSB to get the additional MHz which could get you 3000MHz while keeping the system stable but proper voltages will have to be adjusted.

[RickNorbat]

Hi 

 

thanks for a detailed description of your problems. I got the exact same hardware as you (different psu and graphic card) with the same issue. I also used my ram at 3000MHz, but I will now try the solution explained here and set the freq to 2933MHz and see if it also will help me. 

 

I also OC my system to 4.8GHz, but I used the automatic "bios software". Can you please share your manual settings? I'm not to much into OC, but know that the manual OC tuning is the correct way to do it.

[JohnC]

I've just registered with this site to thank you for creating this thread. Especially to Chris who provided very comprehensive details of his setup and problem.

 

I've had exactly the same problem with the same motherboard with 4 x 8G Corsair 3200 memory chips.

 

I have no experience of overclocking but set my DRAM frequency to 2933MHz (from 3200MHz) and the problem has gone away.

 

The company who built my computer claimed to have done testing and QC (and took three weeks to build it!) but they obviously didn't shutdown as it would not have restarted without a power unplug / wait for the orange LED to go off then power up again. It drove me nuts but luckily this thread was the third match on Google.

 

Once again THANK YOU VERY MUCH!!!

 

John

[Danieldk]

I've been looking for solutions for the exact same problem for days (same mobo with similar specs w/ corsair 3000Hz RAM), as I had the exact same problem like ChrisBox. Thank you very much Windows7ge, it's all fixed now!!

[Andylawson]

Had this experience with my first and only ever ASUS motherboard, worst pile of crap i have ever installed.

installed a gigabyte mobo and used the same components, no issues worked for years until it was replaced.

DON'T BUY ASUS "EVER"!!!

 

[C0RSA1R]

I know this is severely old, but I had the same issue as OP here and had a slightly different fix. Created an account just to share in case someone else finds themselves in the same situation.

 

I didn't downclock the ram speed as suggested above, I merely changed the BCLK Frequency: DRAM Frequency Ratio setting from Auto to 100:100. Kept everything else about my factory XMP profile the same. Now I can boot and restart without any issue.

 

Other info follows for those interested...

 

CPU: 8700K

Cooler: Corsair H100i

Mobo: ASUS ROG Maximus Code

GPU: 3090 FE

PSU: EVGA G2 1300w

RAM: was 32gb of Corsair vengeance LPX 3200mhz CL16. Quite literally upgraded today to 64gb and the issue became worse.

 

Used to only have to power cycle after a restart, but now it advanced to every time I turned off the computer I had to flick the PSU switch and press the power button to completely drain all power. Then flick back on and it would boot.