ASROCK B250M-HDV. Problem CPU C-state and M.2 Slot
Printed From: ASRock.com
Category: Technical Support
Forum Name: Intel Motherboards
Forum Description: Question about ASRock Intel Motherboards
URL: https://forum.asrock.com/forum_posts.asp?TID=5793
Printed Date: 19 Jul 2025 at 12:55am
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Topic: ASROCK B250M-HDV. Problem CPU C-state and M.2 Slot
Posted By: By_Zaca
Subject: ASROCK B250M-HDV. Problem CPU C-state and M.2 Slot
Date Posted: 06 Aug 2017 at 1:39am
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Hi, I bought the ASROCK B250M-HDV 4 months ago. Since when I bought, I have 2 problems: -Reboot random -M.2 SSD does not recognise sometimes Current Setup: ASROCK B250M-HDV (bios 2.20) Pentium G4600 8GB 2400Mhz Crucial CT8G4DFD824A SSD M.2 Samsung Evo 850 250GB Corsair CX500M -Random Restarts: If the CPU C-state is enabled, the OS restarts 5 seconds after going to the desktop screen (tested with Windows 10 PRO and Ubuntu 17.04). If the CPU C-state is disabled, reboots are very random. Sometimes it restarts 5 times in a day and sometimes I can stay for 5 to 7 days without restarting. -M.2 SSD does not recognise sometimes When turning on the computer or after some restart, sometimes the ssd installed in port M.2 is not recognised. And when it's not recognised, it takes about 10 seconds to get into the bios settings. I need to turn off and turn on again (restarting wont work) until ssd is recognised. And when is recognised, i need to set the M.2 has first boot again. Sometimes it works on the first try and sometimes on the third try. I've been testing: Another CPU (i3 7100) Another RAM (Kingston, but I do not remember the exact model) Connecting the M.2 SSD to another motherboard (worked without any problems) Another PSU (ocz modxstram 500w and another "generic" psu) The only log I can see through "View event logs" is: Level: Critical Source: Kernel Power Description: The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly. I am available to try Beta Bios. I am IT technician and i have advanced knowledge. My first motherboard was ASROCK K7VM3. Good old times... :D Sorry for my bad english :( Thanks!!
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Replies:
Posted By: By_Zaca
Date Posted: 10 Aug 2017 at 11:44pm
| Doing a lot of tests trying to figure out what is happening, I discovered something. If I a set the CPU voltage manually, the computer doesn't restart any more with CPU C-State enabled. I am with 25 Hours up time and no restarts at all (yet) |
Posted By: parsec
Date Posted: 11 Aug 2017 at 11:18am
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Your restart problem reminds me of the problem first discovered with Intel Haswell CPUs and low to average quality, older PC PSUs. When C States were enabled, the processor could go into such a low power state that the load on the +12V rail was so low, it would cause the +12V rail to go out of its voltage range specification (usually to high) and the PSU would shut off or restart due to the over voltage protection activating. You are using Skylake and Kaby Lake processors, which do not use the Haswell internal voltage regulators, but they are both low power usage processors, so it makes me wonder. You mentioned you are using the 2.20 UEFI/BIOS version. Part of the description of that version is: 1.Update CPU C-state auto rule. Which usually means whether or not the Auto setting for a C State is enabled or disabled, but it may have another affect too. Question, there are multiple C State options. Which one are you enabling and disabling? All/Global C State support? C3 C State? C6? C7? Package C State support? When you say you manually set the CPU voltage, what VCore mode did you use? Fixed? Offset? Auto VCore is Adaptive voltage, which can cause a very low VCore when C States are enabled. Your "generic" PSUs may not be able to have such a low load on the +12V rail. Are you using the Intel iGPU, or a video card? Do you have any fans connected to the board? What CPU cooler are you using? ------------- http://valid.x86.fr/48rujh" rel="nofollow"> 
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By_Zaca wrote:Posted By: By_Zaca
Date Posted: 11 Aug 2017 at 11:06pm
Doing more tests, and tried every combination. If I enable C1E or C3 or C1E + C3 on the same time, the computer restart after going to the desktop. Doesn't matter if C6, C7 or Package C State Support is enabled or disabled. When i set the CPU voltage manually, i can enable everything and no more restarts (at least, i was 48 hours up time until i needed to restart to try other settings).
Fixed at v1.050.
Right now, I dont have other PSU to test again. But according to this site: http://www.corsair.com/en-us/blog/2013/may/haswell-compatibility-with-corsair-power-supplies the CX500M is "Likely compatible - currently validating" with haswell cpus.
Intel iGPU. Next week I will be using a video card.
Nope. I am using only the cpu fan (the original one who came with the Pentium G4600). Thanks in advance!!
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Posted By: gfonseca
Date Posted: 10 Jan 2018 at 5:40pm
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I'm having the same problem, just bought an Asrock B250M-HDV and Pentium G4560 (kaby lake), and it seems this board has a bug with pentium kaby lake series. I'm not intended to do overclock, I just want to use it as workstation at stock values, I never changed any clock or whatever, just got the PC, plugged all the stuff and turned it on, and I cannot even install Windows!! The board shuts down as soon as Windows starts to install! So I did what you suggested, set vCore fixed (set it to 1.032 but actually I don't have a clue the right value) as the automatic one seemed not to be enough (it was around 0.97x v) and everything worked fine! Got windows installed and everythink up and running well. But I'm scared of setting a vcore too high and damage the CPU. I would like Asrock helped us with an update or support.
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Posted By: By_Zaca
Date Posted: 10 Jan 2018 at 8:42pm
| I downgraded to bios v1.10 and solve the problem. After downgrade, reset the bios and keep all cpu stuff as default. |
Posted By: gfonseca
Date Posted: 12 Jan 2018 at 11:02pm
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" rel="nofollow - hmmm good to know! But 1.10 seems too old. Have any bug with it?
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Posted By: gfonseca
Date Posted: 15 Jan 2018 at 6:18am
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Hi friends, I nailed the problem and finally found what was going on. The problem was the PSU.. user PARSEC above was RIGHT. I changed my PSU for another newer and tada!! Now I can run the system TOTALLY stable, with vcore in auto, everything enabled! 3 days turned on and 100% ok. I just don't know WHY because I was using a Corsair VX550w which manufacturer stated as fully Haswell compatible, but maybe they never tested LOL. Now I'm using a generic PSU of 2007 but it is ATX 2.3 compliant and everything is running fine. Thanks.
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