Question PC randomly reboots, tried a lot, but the only "fix" seems to be to undervolt Ryzen 3600 ?

Jan 22, 2022
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Hey everyone, I've been running into some weird issues. I'm very new to the whole PC thing, basically build a new PC, tried to educate myself. I currently run (used parts, but from trustworthy persons):

Ryzen 3600 CPU
MSI tomahawk max II mainboard
GTX 970 GPU
Seasonic focus GX 850w PSU (this one I got new, to replace the old PSU, because I thought that was the issue)
16gb Corsair vengeance RAM (3200mhz)

I built the PC around a week ago. Since the first boot my PC would randomly reboot when under minimal load (watching youtube, installing software, even when opening a new tab). If I run prime95 it makes my PC reboot after literally 1 second. Temperatures were no issue at all, so that was not the cause. So basically the PC was unusable.

After a week of testing all kind of things (switched RAM, new mainboard, new PSU, cleared bios CMOS, unplugged everything multiple times, updated drivers, cleaned everything), I was ready to give up. Only thing I couldn't get my hands on was a new CPU to test. That was also the thing I was most afraid of, since that CPU cost me quite a bit.

Anyways, today I stumbled upon the practice of undervolting the CPU. I figured I'd give it a try, since I had no more hope left, also couldn't find a solution online for my problems. And interestingly enough, my PC is now running! I had to undervolt the voltage down from 1.35 to 1.30, with these settings I could run cinebench and prime95 for 20 minutes without my PC crashing/rebooting (I manually ended the benchmarks at that point). I did not have to underclock the CPU, only had to undervolt. So my Ryzen still runs at the 3.6ghz. This also fixed the red CPU LED on my mainboard, which was telling me something was wrong with the CPU.

While I'm happy that my PC is now "working", I also feel weird for having to undervolt my CPU for it to run. I don't even know if this is good in the long term, or if this mix might stop working soon, maybe someone could chime in on that? I guess I'm just looking for your guys input on this situation, since I don't feel fully comfortable with it and am wondering if I'm missing something. Feels like something is wrong, since I have to take these extra measures to make my PC run. Any help and input would be much appreciated, thank you!
 

Vic 40

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Motherboard runs last bios?

For the cpu, if it's stable at that voltage are you fine, is even better for it to run lower voltage, lower voltage means lower temps. Does it also boost to max turbo?

What cooler are you using? Was the reboot not a temp problem i'm wondering.
 
Jan 22, 2022
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Motherboard runs last bios?

For the cpu, if it's stable at that voltage are you fine, is even better for it to run lower voltage, lower voltage means lower temps. Does it also boost to max turbo?

What cooler are you using? Was the reboot not a temp problem i'm wondering.
Thank you very much for your reply, much appreciated!

To answer your questions, yes, the motherboard is on the last bios.
I'm using the stock cooler for now (will upgrade to a Cooler Master Evo 212), but I can say with certainty that temperatures were not the issue, since I did monitor them. The reboot would happen at around 35 or 40 degrees celcius for example, many times. While doing simple things like browsing the web. The reboot also got more and more frequent.
How could I find out if my CPU boosts to max turbo? I have not heard about that before.

I'm relieved to hear that the low voltage is not a bad thing! I was just a bit unsure of it all, since I figured a "working" cpu should not need me to adjust voltage, so I guess I'm afraid that these signs could lead to more issues with this CPU in the long run.


Since lowering the voltage, I did not have any crash. I was also able to run prime95 with small FFT for 1 hour (after that I closed it manually), even with max temps at 80 degrees, no crash. So that's good I guess, but it worries me that I had to adjust voltage for this to work, for whatever reason. And also that the crashes kept getting more frequent (had them every 10 minutes at one point).
 
Jan 22, 2022
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It is weird that you have to undervolt from the get-go, might want to talk to the shop you bought it from, if weird issues when at stock settings like unstable pc because of this is probably reason for rma.
Unfortunately I bought it used, from a trustworthy person tho. So I pretty much have to work with the CPU :( That person did not have any of these issues with the CPU. Maybe my motherboard is weird with that CPU? It's the MSI Tomahawk Max II...I got the same motherboard again to test, same crashes. I was thinking my initial one was broken, but I guess it was not.
 
Jan 22, 2022
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I agree it is weird that undervolting is necessary to prevent a crash....

Have you ever reset CMOS since you built the system? I'd suggest doing it both by shorting the jumper and by taking out the coin-cell battery. It's not hard, might be worth trying if you haven't done both yet.
Thank you for chiming in. Yes, I did reset/clear the CMOS by shorting the jumper. Did not help though :(
 

Wolfshadw

Titan
Moderator
Just search this issue.
Same problem developed 1 hour ago.
Ryzen 5950x Crosshair VIII Formula 6900xt 32Gb 3600 G Skill Couple WD Black M2

BIOS current version.

Left PC on, came home, had rebooted, and BIOS showed HDD fault code. PSU on and off, rebooted fine all normal.
30 mins into game, Ghz dropped to .5.

Cleared CMOS, reset DOCP etc, all fine back to 4.9Ghz.

30 mins again dropped down.

Event Viewer shows a windows update.

Will update if fixed - going to be looking at power plan.

Windows 11
@IIIISubzeroIIII

Please do not hijack threads. If you are experiencing a similar issue, please start your own thread so it may be handled separately from this one.

Wolfshadw
Moderator
 
Jan 22, 2022
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Since it seems to work undervolted should you be fine.Maybe current bios is not the most stable, who knows. Can wait for a newer bios and see if it fixes the voltages.
I'm glad to hear that it's ok with the lower voltage! I will wait for a bios update and then test it again, until then I hope my system works properly. So far it's working without issues for 2 days now.

I should mention that my mainboard is quite new I think, it's the Tomahawk Max 2, so a newer version of the regular Tomahawk Max. Maybe it really is instability due to that.
 
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Jan 22, 2022
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You'd think it would be better as V2 .....
I agree :D at this point the mainboard or the cpu are the only suspects I have left. and since the person that owned the cpu before me had no issue, I think its the mainboard. well, at least I can run the PC now (so far), I hope no more crashes along the line with my undervolting settings.
 
Jan 22, 2022
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Crossing my fingers for you.😁
Thank you! And also thanks for your help :) I had one last idea, maybe it could make sense to install an older bios? If thats possible, maybe it would be stable under an older build, just a thought.
Currently I run the newest build of the MSI Click Bios, which is from 27/09/2021.
 
Thank you! And also thanks for your help :) I had one last idea, maybe it could make sense to install an older bios? If thats possible, maybe it would be stable under an older build, just a thought.
Currently I run the newest build of the MSI Click Bios, which is from 27/09/2021.
It might help simply because it's a change. What revision do you plan on reverting to? I'd suggest going back to the shipping BIOS for that board: version H0. It has a mature AGESA for your Matisse (3000) CPU but will not support a Vermeer (5000) CPU.

I had some difficulty getting back into Windows when reverting BIOS on my son's MSI B450 Mortar and 3700X CPU. I eventually gave up and updated back to the latest. Hopefully you don't experience the same issue.

Your problem really is quite strange since even if over-volting at stock setting it should simply run hot but not be unstable. It's really not typical so anything you do is a bit of an experiment. Don't be surprised if it does not work.
 
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Jan 22, 2022
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It might work, would personally use the previous bios and see if that makes things better.
I think I will go for this! Just ordered a USB stick so I can do this.

@drea.drechsler I might go for that as a last resort, thank you!

I've got bad news tho, I did run cinebench with my now undervolted ryzen 3600 and the results are worse than those for a stock ryzen 3600, by quite a bit actually. I'm somewhere between a ryzen 2600 and a ryzen 3600 now. So I guess undervolting does also decrease performance? :( Now I really need to fix this, since I want to use my ryzen 3600 for what it is hah. I'm hoping the bios downgrade will help!
 
Jan 22, 2022
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@Vic 40 Omg, I think I fixed it! :D So I've found a post where someone mentioned that default bios settings are not to be trusted, especially for the CPU. So just because the bios sets the CPU voltage to "auto" by default, does not mean thats the real voltage the CPU needs to work properly. So they suggested to instead choose "voltage offset" in the bios.
So I did that, a voltage offset of 0.1v was suggested and lo and behold, I'm able to run prime95 now and the CPU is at full power! I can confirm this by doing cinebench, I'm getting the expected score for a ryzen 3600 at stock! Before that (when undervolting) I was getting 1000-2000 points less on the score, which made my 3600 into a 2600 pretty much. I'm so happy it's at full power now!

To be honest I don't fully understand how the voltage offset works, but it's working! Now let's just hope it stays that way hah. But so far that's the first time the CPU is running at full power without crashes in prime95 for example, before that it would literally crash in 1-2 seconds.

And regarding your suggestion, I do have the newest chipset drivers installed, that was one of the first things I did.
 
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Jan 22, 2022
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Good to hear! Was looking for something like that, good you found it first.
Thank you very much! Once this stays stable for a few days, I'll report back, just so anyone else that has this issue will know that this is the fix. It's looking great so far, I'm putting my PC in all the typical scenarios where it used to crash and it does indeed not crash now, runs super smooth.

I have to say tho, I'm a bit mad at MSI for making their bios do this type of "mistake". Been stressful times, so much researching, testing, replacing hardware. Phew. I guess the good part is that I learned a lot about PC's and feel more comfortable with it, so thats something. :)

Thanks again to everyone that helped me in here, it is much appreciated.
 
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Karadjgne

Titan
Ambassador
Use HWInfo64 (not Hwmonitor). It takes a little getting used to reading, but it's worth it. There's several things about your cpu that just don't add up, but part of that is using single digits to represent multiple cores.

You read a temp of 80° running P95. Which core. Is it an average reading, the hottest core or hopefully not, the coldest. It's entirely possible, since you are a beginner, that the paste spread on the cpu isn't all that great, and is allowing one or more cores to hit extreme temps, and getting averaged in the total. 5 cores at 70° and 1 core hitting 100° = you crash, but temps can average out closer to 80°.

Same applies for voltages. With Ryzens, there's 3 to pay particular attention too. VID, CPU, SVI2. Vid is what the VRM's supply, cpu is what the cpu demands from the VRM's and SVI2 is what the cpu actually uses. SVI2 and cpu will normally be pretty close, vid a little higher. The offset changes VID. By lowering that, cpu can't demand as much and probably doesn't need to use as much. Temps go down.

Undervolting the wrong way can have funky results. Ryzens boost according to core use, temps and available voltage. So it's not uncommon to see single threaded apps push 1.5v on a single boosted core at max speeds. Apply more cores, voltage goes down, as does boost, to keep steady state temps. By changing the Auto voltage to a static 1.3v, you killed half the boost because now the cores can't hit the target voltage. That's why the offset worked, it lowered VID, but didn't change what the cores actually required.

Look into CoreTuner2. Follow the guide when setting up the bios, and play with the settings a little. It'll run through your chip and help it decide the best stable performance level, which you can tweak as wanted.
 
Jan 23, 2022
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Reboots under minimal loads. Ryzen.

Sounds similar to what I was dealing with on my 3900X. I would get random reboots at idle. NEVER when under load such as rendering or playing a game.

I tried many things. One thing that fixed it was disabling Global C-states in the BIOS. However, this didn't allow the CPU to go fully power efficient on idle. So I looked for other fixes.

Someone in another forum suggested that I play with my CLDO VDDG and CLDO VDDP voltages. It turns out the board was either overvolting these or the CPU didn't like the voltages, so I lowered them a bit. What do you know? All reboot issues gone.

I switched to a 5900X and had never encountered this problem again, everything is stock and working fine, so that particular 3900X of mine had some issues with voltage.

See if disabling global C-states or lowering VDDP and VDDG voltages slightly (by -0.100) helps.