New RTX 5080 won't boot - no signal
Hello everyone
Just bought a new GPU, a Zotac RTX 5080 Solid OC, but can't get it to boot with signal on screen.
Have used DDU to clean all drivers, and here is my specs and what I have tried so far. Would welcome any help with appreciation.
🧾 Summary – RTX 5080 No Signal / VGA LED Issue
🖥️ Hardware
Motherboard: ASUS ROG Strix X570-E Gaming
CPU: Ryzen 9 5900X
RAM: 32 GB Corsair Vengeance DDR4
PSU: Corsair RM1000e (with dedicated 12V-2x6 / 600W GPU cable)
GPU 1 (working): RTX 3080 Ti
GPU 2 (problem): Zotac RTX 5080 Solid OC
⚠️ Main Symptom
5080 produces no POST display output
Motherboard stops at VGA LED (white indicator)
Monitor behavior:
Detects signal input (DisplayPort/HDMI active)
Then shows “No signal”
System remains stable (no reboot loop or instability)
GPU fans spin at startup
GPU 12VHPWR LED is green (power/connector OK)
🔧 Troubleshooting Performed
✔ Power & cabling
PSU confirmed stable (RM1000e)
Dedicated 12V-2x6 cable used
GPU power LED shows green (connection OK)
No signs of power delivery failure
✔ Display & signal
Tested HDMI and DisplayPort
Tested multiple screens (monitor + TV)
Cables and displays work with other GPU
✔ GPU testing
RTX 3080 Ti works perfectly in the same system
RTX 5080:
Installed and reinstalled multiple times
Reseated multiple times
Power cables rechecked and swapped between tests
✔ BIOS / motherboard
BIOS updated to latest stable version
VGA LED consistently triggered only by 5080
CSM / UEFI settings not yet fully tested (planned, last solution?)
PCIe Gen3 forced mode not yet tested (planned, last solution?)
✔ Physical checks
Multiple GPU reseats performed
Power cables reconnected multiple times
Slot contact considered OK since 3080 works reliably
📊 Observations
GPU receives power (fans + green LED)
GPU never completes video output initialization
System consistently stops at VGA stage in POST
No instability or reboot behavior
Entire system works normally with previous GPU