X670E PG Lightning no POST on cold boot

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   I'm having an issue with my ASRock X670E PG Lightning using the latest BIOS 3.40

I'm enable to boot with EXPO on, every time after the power supply has been turned off and back on. Completely cold boot.

I've been on 3.40 for the last 12 days no issues. However, last night I lost power in my house.

PC was off at the time. Tripplite surge protector. A-tier power supply... However, the PC wouldn't boot after that.

Fans on full. RAM and CPU red lights on. Gave it a few minutes, thinking memory training. Haven't had to deal with anything like that since 2023.

No good though. Not booting.

Reset BIOS. (Actually, reinstalled 3.40).. Good to go again. Set up my BIOS how I like it. EXPO on... etc.

Boots up. Ran stress tests. Gamed for an hour. No issues. Shut down, boot up. No issues.

Shut down, turn the power supply off and back on. PC won't boot again. Fans on full, RAM and CPU lights on. Not booting.

Shutdown. I replaced the CMOS battery. Repeat steps. Set up BIOS settings. Shutdown. Then shutdown and turned off power supply. Back on and won't boot.

Rolled back to 3.30. Set up bios. Shut down. Turned off power supply. Turned back on. Booted right back up.

Chances are in the last 12 days since 3.40 release on my motherboard, my power supply had never been turned off. Everything works fine, even under heavy stress. But as soon as the power goes out, I can't boot with 3.40.

It seems I'm not alone. I found a few others on reddit with this issue.

My RAM is TEAMGROUP T-Create Expert CL30 6000MHz. Could be related.

Cheers.

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BeerGogglesFTW Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 17 Sep 2025 Status: Offline Points: 15	Post Options Post Reply Quote BeerGogglesFTW Report Post Thanks(0) Quote Reply Topic: X670E PG Lightning no POST on cold boot Posted: 17 Sep 2025 at 9:24pm
	I'm having an issue with my ASRock X670E PG Lightning using the latest BIOS 3.40 I'm enable to boot with EXPO on, every time after the power supply has been turned off and back on. Completely cold boot. I've been on 3.40 for the last 12 days no issues. However, last night I lost power in my house. PC was off at the time. Tripplite surge protector. A-tier power supply... However, the PC wouldn't boot after that. Fans on full. RAM and CPU red lights on. Gave it a few minutes, thinking memory training. Haven't had to deal with anything like that since 2023. No good though. Not booting. Reset BIOS. (Actually, reinstalled 3.40).. Good to go again. Set up my BIOS how I like it. EXPO on... etc. Boots up. Ran stress tests. Gamed for an hour. No issues. Shut down, boot up. No issues. Shut down, turn the power supply off and back on. PC won't boot again. Fans on full, RAM and CPU lights on. Not booting. Shutdown. I replaced the CMOS battery. Repeat steps. Set up BIOS settings. Shutdown. Then shutdown and turned off power supply. Back on and won't boot. Rolled back to 3.30. Set up bios. Shut down. Turned off power supply. Turned back on. Booted right back up. Chances are in the last 12 days since 3.40 release on my motherboard, my power supply had never been turned off. Everything works fine, even under heavy stress. But as soon as the power goes out, I can't boot with 3.40. It seems I'm not alone. I found a few others on reddit with this issue. My RAM is TEAMGROUP T-Create Expert CL30 6000MHz. Could be related. Cheers.

Xaltar Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: 16 May 2015 Location: Europe Status: Offline Points: 29793	Post Options Post Reply Quote Xaltar Report Post Thanks(0) Quote Reply Posted: 17 Sep 2025 at 9:37pm
	Open a support ticket with ASRock. Unless it turns out to be a setting in the BIOS there isn't much anyone here on the forums can do to help. This will require ASRock's attention.


vrock442 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 19 Sep 2025 Status: Offline Points: 45	Post Options Post Reply Quote vrock442 Report Post Thanks(0) Quote Reply Posted: 19 Sep 2025 at 5:18am
	I have similar issue and already posted it on another thread. But I have not used the PC long enough to test previous BIOS versions. Did you just first encounter this problem after updating BIOS to 3.40? And never before? Did you manually set Context Memory Restore or Power Down Enabled, or some other BIOS setting except EXPO OC profile?

DontAsk Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 11 hours 41 minutes ago Status: Offline Points: 30	Post Options Post Reply Quote DontAsk Report Post Thanks(0) Quote Reply Posted: 11 hours 22 minutes ago at 5:49pm
	Hi, my system is also affected by this bug in the BIOS 3.40. Reverting to an older BIOS like 3.30, 3.25, 3.20, etc. will immediately resolve this cold boot issue, which only occurs after unplugging the PC from the power supply. CPU: 7900X3d RAM: Corsair Vengeance 64GB Kit CMK64GX5M2B6000Z30 @ 6000 MHz and activated EXPO I reverted back to BIOS 3.30 as long as this bug in 3.40 or a newer one is not fixed.

NDRE28 Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 08 Sep 2024 Location: Romania Status: Offline Points: 1955	Post Options Post Reply Quote NDRE28 Report Post Thanks(0) Quote Reply Posted: 5 hours 21 minutes ago at 11:50pm
	Hi! Everyone here posting about EXPO RAM issues seem to have the same speed: EXPO-6000. I'd suggest loading the EXPO-6000 profile, then changing the DRAM speed to DDR5-5600. This way, the timings & voltage will remain as set by the EXPO profile, and only the frequency will be lowered. Please keep in mind that every AMD CPU on the AM5 platform supports officially up to DDR5-5600! Running memory above that frequency successfully is not a given! Some IMCs will handle higher frequencies, some won't! It's all about the silicone lottery.

DontAsk Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 11 hours 41 minutes ago Status: Offline Points: 30	Post Options Post Reply Quote DontAsk Report Post Thanks(0) Quote Reply Posted: 20 minutes ago at 4:51am
	Hi, in this case it has nothing to do with the EXPO setting and also if it's set to 6000 MT/s or even higher. The issue is that after unplugging the power supply only the BIOS 3.40 can't boot the PC anymore. So if you e.g. lower the RAM frequency and it starts thereafter then that indicates that either not all relevant BIOS settings for a successful boot process are stored in the CMOS correctly or that the stored values are incorrectly evaluated during the boot process after a power outage. If I use BIOS 3.30, 3.25, 3.20 and even older ones this issue doesn't exist at all. The RAM runs even with EXPO 6200 MT/s, CL28, FCLK 2200, UCLK=MEMCLK, and VSOC 1.225V stable as a rock. So long story short, if all other BIOS versions don't have this issue except the 3.40 then it's clear that there is a bug in BIOS 3.40.