PC Boots but No Video Output

gupott

gupott

gupott

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252
I am having an ongoing issue with my PC which is driving me crazy. Apologies for the upcoming long post!

The PC boots normally, but I have no video output during boot. If I power the PC off, and then turn off at the PSU and hold the on/off, the PC will boot normally about 1 in 5 attempt. The OS loads in the background, and if I get the prompts correct by guessing, I can get into the system, where everything is fine. If I don't, it sits stubbornly on a blank screen.

The things I have noted are
  • No BIOS splash
  • No pre‑boot password prompt
  • No GRUB
  • No KDE login
  • Screen stays black
  • The OS loads in the background (I can log in blind sometimes by guessing where I am in the process)
  • Occasionally, after a PSU power‑cycle, I briefly see the pre‑BIOS hyphen or BIOS screen
  • The issue affects both DisplayPort and HDMI
I am not sure this is a boot failure perhaps a display initialization failure?? My system is
  • CPU: Ryzen 7 9800X3D
  • GPU: RTX 5080 Founders Edition
  • Motherboard: ASRock X870E Taichi
  • Monitor: Samsung Odyssey Neo G8 (G85NB)
  • OS: Dual‑boot KDE Plasma (Linux) + Windows 11 - same issue on both OS
  • Storage: Gen5 + Gen4 NVMe drives
I have tried

bios/Firmware
  • Updated motherboard BIOS to 4.04
  • Disabled Fast Boot
  • Disabled CSM
  • Forced PCIe Link Speed = Gen4
  • Enabled Above 4G Decoding
  • Disabled Memory Context Restore
  • Disabled Power Down Mode
  • Set RAM to DDR5‑5600 for stability
  • Set primary GPU to dGPU/PCIe (where available)

Monitor / GPU​

  • Disabled Adaptive Sync (VRR)
  • HDR already off
  • Tried all three DisplayPort ports
  • Tried HDMI
  • Fully power‑cycled the monitor
  • Swapped cables
  • Verified monitor works perfectly with another machine (Intel NUC)

Current Behaviour​

  • System boots, keyboard lights up, drives spin, OS loads
  • Monitor wakes briefly but fails to sync
  • No BIOS or early‑boot output
  • Only very occasionally shows BIOS after a full PSU drain
  • Once in the OS (if I get a picture), everything works perfectly!!!
  • Another with an intel nuc on it works fine!
This appears to be a GPU → monitor handshake failure during early boot, not a hardware fault.

Does anyone have any tips, insight or recommendations on how to fix??

Thanks for reading!
 
What boot manager are you using? I’m leaning towards some code instruction (hoping) only because of the psu discharge bit. Perhaps some code is being written to some flash memory on your motherboard or gpu. As decto said try a live usb and disconnect your dual boot drive. I would try a windows 10 live usb.
 
Thank you for all the replies, it is much appreciated. I will try and answer one by one.

Minibiker said:
May not be the case but try 1 stick of RAM at a time, have you tried another HDMI or other display cables?
Click to expand...
I have not done this yet.

Gray2233 said:
Try running from the iGPU on the motherboard with and without the GPU physically installed, see what happens.
Click to expand...
On the list to do now!

freddie64 said:
Has it done this since you first built the PC?

What PSU and RAM?

Do any debug LED's stay lit up?
Click to expand...
I don't think it has done it where it has been such an issue, I think perhaps it has got worse as I have updated bios versions on the motherboard which I was keen to do as there has been issues with the cpus and the board, which were supposedly fixed by the new bios versions. The PSU is a Corsair RM1000x 1000 Watt Fully Modular 80+ Gold. and the ram is 32GB (2x16GB) Corsair DDR5 Vengeance Grey, PC5-48000 (6000), Non-ECC Unbuffered, CAS 30, 1.4V, AMD/XMP. As for the debug LEDs, I have not looked, I will next time, its currently showing code 47 as I type.

aaronyuri said:
Has it always done this, or is this a new behaviour?
Click to expand...
I think it is worse, particularly as I have upgraded bios, and upgraded the GPU (from a 3080 to a 5080). But as I have lived with it for a while there was no obvious point where it went from not being a problem, to it being a problem, basically I could get in to the machine almost every time until i couldnt easily.

decto said:
Is it the same with a Live USB?
Click to expand...
Yes, with windows 11 or KDE Neon too. Yesterday was having the behaviour on both drives, even with one hdd installed, it doesnt seem to make a difference.

sg0 said:
What boot manager are you using? I’m leaning towards some code instruction (hoping) only because of the psu discharge bit. Perhaps some code is being written to some flash memory on your motherboard or gpu. As decto said try a live usb and disconnect your dual boot drive. I would try a windows 10 live usb.
Click to expand...
I installed windows 11 first, and then KDE neon later, so grub is in use now, but I get the same behaviour with ubuntu (so grub again), and windows etc. When you try the live usb, yesterday I installed kde neon from a usb, and I was having the same issues, I was trying to see when to press to load from usb.

Some extra info
I got in first time this morning, no screen visible but inputted passwords and what I thought was the correct time. So the first screen I can actually see is KDE Neon home page. Later, I let the system restart to complete some updates, but I could not get back to the desktop and I was worried I did not want to interupt any updates. Anyway, I left for 20 mins, restarted and tried again, I could not get in. I then switched cable on a whim, from display port to hdmi, and I was presented with the home screen. I will restart again momentarily and see what happens!
 
I’ve now tested the system with a different monitor — a Dell P2219H — using both HDMI and DisplayPort. With the Dell connected, the PC boots perfectly every single time. I can see BIOS, the pre‑boot password prompt, GRUB, KDE, everything. Cold boots and reboots all work flawlessly. No blank screen at any stage.

I then took the same cables that worked with the Dell and reconnected them to my Samsung Odyssey Neo G8 (G85NB). The problem immediately returned. No BIOS, no pre‑boot output, no GRUB, no KDE login — just a blank screen, even though the PC is clearly booting in the background.

I tested both HDMI and DisplayPort on the Samsung. Neither worked during early boot. The only way I could get the Samsung to show anything was to hot‑swap the DisplayPort cable between ports after I was already logged into the OS. Once the NVIDIA driver is active, the Samsung works normally.

Meanwhile, the HDMI connection to my Intel NUC continues to work perfectly on the Samsung at all times.

Summary of what this seems to show:

  • The PC itself is fine (GPU, motherboard, BIOS, RAM, PSU all behaving normally).
  • The Dell monitor accepts the GPU’s early‑boot signal every time.
  • The Samsung G85NB consistently fails to sync during early boot, on both HDMI and DP.
  • The Samsung only works once the OS loads the NVIDIA driver and forces a stable mode.
  • Hot‑swapping DP ports after login wakes the Samsung, but it never shows BIOS output.
At this point it looks like a display‑initialisation/handshake issue specifically between the RTX 5080 and the Samsung Neo G8 during early boot, rather than a fault with the PC itself.

If anyone has experience with Samsung G7/G8/G9 models and NVIDIA 40/50‑series cards on AM5 boards, or knows of specific monitor settings/firmware quirks that affect early‑boot DP/HDMI handshake, I’d really appreciate any insight.
 
Having a quick search I found some Samsung forums where a user was reporting a similar issue with 4080 card. That user seems to have discovered it as an issue specifically with DP and seems to be able to use HDMI OK.

Thread was started back in 2024, but might find something useful and wanted to share it

Also just found a link to Nvidia forums where the same issue is mentioned and it could be driver related using DP. NVidia thread here also suggests trying to switch to HDMI
 
aaronyuri said:
Check if you're running the latest firmware for the monitor and update it if not.
Click to expand...
Thank you, yes, I have gone around making sure everything is on the latest firmware and bios etc.

nade said:
Having a quick search I found some Samsung forums where a user was reporting a similar issue with 4080 card. That user seems to have discovered it as an issue specifically with DP and seems to be able to use HDMI OK.

Thread was started back in 2024, but might find something useful and wanted to share it
https://us.community.samsung.com/t5/Monitors-and-Memory/Samsung-Odyssey-G8-G80SD-32-inch-Intermittent-Black-Screen/td-p/3090809/page/22
Also just found a link to Nvidia forums where the same issue is mentioned and it could be driver related using DP. NVidia thread here also suggests trying to switch to HDMI
https://www.nvidia.com/en-us/geforc...n-classhighlightodysseyspan-span-classhighli/
Click to expand...
Thank you I had a read of those, hdmi is slightly better for me, but only slightly.

Latest update.

Symptoms
  • No BIOS splash, no GRUB menu, no LUKS prompt visible on either DisplayPort or HDMI.
  • Monitor wakes, shows input icon, then “No Signal”.
  • This repeats at the exact moments BIOS/GRUB/LUKS should appear.
  • Once the OS loads the NVIDIA driver, the display works perfectly at 4K 240 Hz.
  • HDMI shows slightly more during late boot (occasional flashes), but still no usable output until the OS loads.

Through testing, the following have been eliminated as causes:​

Not the monitor
  • Same behaviour on HDMI and DP
  • Same behaviour across multiple reboots
  • G8 quirks alone cannot explain identical HDMI failure

Not the cable or port​

  • Multiple cables tested
  • Both HDMI and DP behave identically until OS driver loads

Not GRUB or Linux​

  • Changing GRUB resolution (4K, 1080p, etc.) made no difference
  • LUKS prompt is running — it’s just invisible
  • KDE works perfectly once the driver loads

Not encryption or OS configuration​

  • Issue occurs before the OS even starts loading
  • Windows shows the same lack of BIOS output

Not CSM​

  • Enabling CSM breaks the boot chain (expected on pure‑UEFI systems)
The issue is now strongly pointing to a firmware‑level timing problem between the RTX 5080 and the ASRock X870E motherboard during early boot.

In more detail:

The Ryzen 9800X3D has​

All video must come from the RTX 5080.

The RTX 5080 relies on its​

If the GOP initialises late or incorrectly, you get a black screen until the OS loads the full driver.

The X870E chipset is still receiving major AGESA updates​

Early BIOS versions often have issues with:
  • PCIe 5.0 GPU initialisation
  • PCIe 5.0 NVMe delaying POST
  • GPU enumeration timing
  • Early‑boot video handoff

The Samsung Neo G8 is extremely strict about timing​

It rejects unstable or incomplete early‑boot modes instantly.

HDMI showing​

This is appears to be classic “GOP initialisation delay” behaviour.

Conclusion:
The GPU is not being initialised early enough by the motherboard firmware, so no valid video mode is available until the OS driver loads.

This matches known behaviour on:
  • early RTX 4080/4090 firmware
  • early RTX 5080/5090 firmware
  • early AM5 BIOS versions
  • PCIe 5.0 NVMe + PCIe 5.0 GPU combinations
I have to go through the bios again later, looking to stabilise early‑boot GPU initialisation:
  1. Primary Graphics Adapter → PCIe/PEG
  2. Initial Display Output → PCIe Slot 1
  3. Above 4G Decoding → Disabled (temporarily)
  4. PCIe Link Speed → Auto (not Gen 5)
  5. PCIe ASPM → Disabled
  6. Re‑Size BAR → Enabled (or Disabled if needed)
  7. Fast Boot → Disabled
  8. CSM → Disabled (required for UEFI boot)
These will be tested next.
 
There is a Windows update (KB5074109) that is causing problems with some Nvidia users. (and a lot of other users)

Might be worth checking if you have this update and uninstall it if you have.
 
I might be having a similar occurrence, though mine just happens now and again. It actually happened today for the first time in a while with exact symptoms as yourself - pc booting with keyboard and mouse but nothing on screen. The last time this happened I just left it, and it eventually just rebooted itself to Windows but on previous occasions I have had to do a hard reset.

I'm not sure why, but when it booted to nothing on screen today, I removed the DP cable from the back of my 4080 and placed it into the next DP connection on the back of the 4080, and I got a display to the monitor. I did have a Windows update yesterday, so I am hoping like another person mentioned that this is the culprit and therefore a fix will be released to fix the previous update.
 
Its insanely annoying I have decided! I am generally booting to KDE, although windows is a choice on boot, but I don't see this obviously. I think the problem is 5080 gpu and X870E Taichi mobo aren’t completing early‑boot GPU initialisation, so the monitor never receives a valid video mode during BIOS/GRUB/LUKS. Once the OS loads the NVIDIA driver, the GPU finally outputs a proper signal and the display works normally.

I am actually wondering about using a small simple screen, like 7", via hdmi from the card, so I can actually see what is happening.
 
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i had a similar issue like this with the black screen, not sure if its alreday been mentioned above but i had to set my New GPU i installed to PCI-E 3.0 in the BIOS rather than 5 or 4 as my riser cable would not support it and gave me a Black screen on boot. maybe you have a similer thing with the slot.

P
 
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I have a similar problem for a number of months now. Manifestation was a bit different (and maybe more severe early, maybe linked to early BIOS problems?)

x870e ProArt
9950x3d
5090TUF

Lets start with the good: Under any load PC is perfect. Not overclocked or anything.
Default BIOS settings, updated 2 days ago.
Service checked GPU and PSU, said that the GPU is good (not a very good service, I had major problems with many systems and servers that they misconfigured, just fyi). PSU replaced as they said it failed one test.

At the moment. Most of the times PC boots perfect. But at one random cold boot, screen is black, white led on the board and windows does boot in the background (accessible via RDP) but HWINFO has no dGPU. If I shut down via RDP and start again, all ok.
This is super random...

Is this some soft of "PCIe link training failure"?
 
Koukos said:
I have a similar problem for a number of months now. Manifestation was a bit different (and maybe more severe early, maybe linked to early BIOS problems?)

x870e ProArt
9950x3d
5090TUF

Lets start with the good: Under any load PC is perfect. Not overclocked or anything.
Default BIOS settings, updated 2 days ago.
Service checked GPU and PSU, said that the GPU is good (not a very good service, I had major problems with many systems and servers that they misconfigured, just fyi). PSU replaced as they said it failed one test.

At the moment. Most of the times PC boots perfect. But at one random cold boot, screen is black, white led on the board and windows does boot in the background (accessible via RDP) but HWINFO has no dGPU. If I shut down via RDP and start again, all ok.
This is super random...

Is this some soft of "PCIe link training failure"?
Click to expand...
Are you using a riser cable to connect the GPU to the motherboard ? If so maybe check what the specs are for the cable and set the correct PCIe speed for it in the BIOS as a test to rule it out.
 
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