Processors

[demonak]

Hello

So, i bought ryzen 3950x for replace my old 2700x stable processor and after two weeks i saw random reboots, all setting stock (auto). Then i decided test new PSU and same issue. Replaced new kit 4x32gb F4-3200C16Q-128GVK (tested without xmp) to old 4x16gb M378A2K43CB1-CRC and same problem (all memory kits working fine with ryzen 2600, 2700x). Then after couple tests i found what prime95 small fft fail emideatly after start, some thread not running and sometimes i got bsod and the other stress test OCCT power with avx2 shows many errors after start.

Ok i decide to replace CPU in store, because i think it's faulty / defect and when i recived new one after one month, install and test prime95 small ffts and know what? problem still happend, not running thread and bsod. I Testing many bioses for my board: 5.80, 5.91, 5.93, 5.94, 5.95, 5.99, 6.20, 6.20A, 6.20B, but the problem is not solved. ASRock support not helped, they tested them cpu ryzen 3950x on same board x370 taichi and not could reproduce problem.

I Found solution on internet forums: set cpu offset voltage +0.05v with LLC2(3) or enable PBO (can too hot and throttling) all stable right now and prime95, occt pass without errors and bsods.

But i Want know i recived another defective CPU? or perhaps this is motherboard problem (too much drop voltage on very high cpu load) and i need to return money (because board still under warranty) and buy example new motherboad on x570 or maybe it's bug in AGESA code because i see many other post with the same problem on differents system configuration like x370, x470, x570 + cpu ryzen 3600-3950x. Why I didn’t have problems on processors ryzen 1700, 2600, 2700x?

Just thinking ... maybe after some BIOS/AGESA update on the processors ZEN2 the voltage in the load is too low or idle and this leads to problems like random reboots, bsod.

My Specs:

* CPU: ryzen 3950x(batch 2008)
* Cooler: noctua nh-d15
* MB: Asrock x370 taichi (bios 6.20)
* DRAM: 4x32gb G.Skill F4-3200C16Q-128GVK
* GPU: Palit GTX 1080ti JetStream
* SSD: SAMSUNG 960 EVO MZ-V6E500 500gb, M.2 2280, 1tb HP EX950
* hdd :Toshiba 2x3tb (DT01ACA300), Hitachi 1x3tb (HDS723030ALA640), Seagate 1x3tb (ST3000VX000), 1x8tb Hitachi (HDN728080ALE604), 1x10tb Toshiba (MG06ACA10TE).
* display: BenQ XL2420T 1920*1080 120hz
* case: lian-li v2120
* PSU: Thermaltake TP DPS-G 850W:
+3.3V - 25A, +5V - 25A, +12V - 70.83A, -12V - 0.8A, +5VSB - 3.0A | +3.3+5V (130W), +12V (849.96W), -12V (9.6W), +5VSB (15W)

[mirkwoodape]

I just got also 3950x (just snatched one used), replacing my 1800X on X370 Professional Gaming. I had latest BIOS 6.40 when 3950X couldn't boot at all, stuck at 36 status LED. Been replacing it wit 1800X back and forth just to downgrade BIOS 6.40 (failed) --> 6.20 (failed) > 5.8 (succeed to boot). That's also came with lot of issues as yours, few of them:

• Random reboot (automatically entering BIOS, detecting 0MB RAM), sometimes cold boot, not even able to go to BIOS. Clear CMOS didn't work, but I know the processor managed to boot in this BIOS (at least). This was solved by removing one of my DDR (G.Skill TridentZ 2x8GB 3200 CL14 GTZ), enter BIOS quickly, and set DDR voltage a bit higher than before (usually 1.35v for XMP 3200Mhz CL14, now I have to set it at 1.38v).
• Slight undervolt by offset (i know lot of people manage to put -0.05 or eve -0.1v), but for my case, even -0.01875v will result in very similar random reboot like yours. Solution for me, didn't even touch the vcore, I left it at auto.
• Even with default vcore (LLC 2), prime95 small fft also failed within few seconds (blend somehow never fails). Cinebench also never fails, Ryzen Master stress test also works fine. So I just ignore this prime95 crash.

In short, I don't think it's the defective CPU, I'll say it's in the motherboard. Most likely, changing to X570 will solve most of the issues you (we) have.

My specs:

* 3950X 
* X370 Professional Gaming BIOS 5.8 (AGESA 1.0.0.3)
* G.Skill TridentZ 2x8GB 3200Mhz CL14 GTZ
* eVGA G2 650W
* MSI GTX1080 GamingX

[mackbolan777]

The poster below and you are correct in that the board is not the best nor recommended for that CPU. As a fellow AsRock owner of an AsRock X570 Phantom Gaming 4S and some discussion on another forum due to a random shutdown problem with error 18, 41 and such we thought the VRM was causing it since AsRock has used the same poor VRM deign for several years. Turned out for me, runnng the 3600X, power delivery wasn't an issue. It was RAM speed but the fact I cannot run my 3733Mhz RAM due to the IF not being stable at 1867 because the BIOS doesn't have a choice for a pure 1866, is probably the board but I am running stable at 3600Mhz RAM speed and 1800Mhz IF. 

During the "dig" for the problem we did uncover that my VRM is the very same used on your board and newer to the X570 and is a bit too weak for a 3900 or 3950X and certainly not enough to hold a 5000 series CPU. Vdroop would be the concern as well as the IF splits not matching AMD's specs. So the consensus is to avoid AsRock motherboards for AMD period. Never cared for AsRock, bought the board because it was on sale. Trying to save $50 was a stupid mistake.

I personally find their BIOS to be shoddy at best, RAM support inadequate and their support team is most unhelpful. I waited 4 months for them to come out with the 3.20 BIOS so I could run my 3733 at 3733 only to find that the extra IF speed was a no go. The PC would run fine for days then crash or restart for no apparent reason. Then it got worse doing it more in games then just browsing. Finally me and a few electronic engineers figured it out. I might replace my motherboard just for that reason and to see if my alternate choice runs the RAM correctly. But it's working ok now, so not sure yet. 

My alternate choice is a Gigabyte X570 Aurous Elite or Master. That has a much, much better VRM design and is very capable of moving on to the 5000 series if I choose to. Can't even find one right now, lol. But when they come around again a 5600X might be in the picture for me. 

Like I said, at the end of the day that board brand is at fault. They're not fixing anything soon. If yours is working ok, then you're in my position of indecision of whether or not to get a different board and sell this junk. 

[hyevltg3]

Just wanted to chime in and confirm my setup is working thanks to this forum post.

• Asrock Fatal1ty X370 Professional Gaming
• AMD 3950X
• Bios 6.40

Thank you a lot @demonak, saved me going over 2 months of headaches and assuming I bought a bunked 3950X during this PC Component scarcity 2020.

All I needed to do was re-visit BIOS > AMD CBS >> "something-something" Override

As I had the new Bios 6.40 installed (after a massive headache of following another forums member that mentioned that 5.40 works for 3950X instead of 5.80. Loaded 3950X on pre-installed 5.30 using my old 1700X, worked for <10mins and froze. After much researching and countless suggestions to update to 5.80 as indicated at Asrock's CPU Support List. I Updated, WITH the 3950X installed, got Bios Interrupted as the system crashed while updating. took a bit of nerve and guts to try my hand at replacing the Bios SMC?SMD?, never desoldered a surface-mounted chip before so this was scary; could have destroyed the rest of the motherboard if I made 1 mistake. Got it done and the chip reads good as fresh 6.40) Was still getting the Freezes and crashes getting into Windows and sometimes Windows never loads as with what a failing CPU symptom looks like (I work in PC repair) after replacing the BIOS chip, with this issue still present I really gave up.

After many attempts and sorrow I landed on this page somehow and followed your raise vcore suggestion. On my way to find this and learning PBO is not Chipset 400 series+ specific, its on 300 as well. I looked deeper in BIOS, found the Override(PBO) page, guess what! it was locked behind an Agreement.

All I needed to do was select Agree and it enables PBO. I am in Windows now on the 3950X typing this. no issues other than a bad TIM application (idles at 70-80c). No vcore raised.

Thanks a bunch Demonak. spent my entire Christmas angry at myself for rushing to get it working, that I skipped the basics of trying to update BIOS on a confirmed crashing machine.