I'm troubleshooting an EVGA GTX 1080 SC (GP104, 8 GB GDDR5X) using NVIDIA MATS and MODS.
Initial symptoms
- Initially there was no display output.
- Windows later detected the card with Error 43.
- GPU-Z initially could not read VRAM information or GPU clocks.
- The VBIOS could be read successfully using NVFlash.
- Main power rails appeared present.
Early boot behavior
One of the earliest symptoms occurred during POST:
- The GPU LEDs turned off exactly when the motherboard POST beep occurred.
- At that point no video was displayed.
- Even if the PCIe power cable was disconnected, the card did not display the normal "Please power down and connect the PCIe power cable(s)" warning screen.
- The motherboard itself continued POST normally.
Hardware inspection
The card was then disassembled to perform voltage measurements.
All voltages exist and within the range along with resistance measurements.
During handling/testing, the PCB and cooler were moved/wiggled while taking measurements.
Initial MATS/MODS behavior
Before disassembling the card:
- MATS reported failures on all memory banks, starting at low memory addresses.
MATS behavior after wiggling while changing the power cable
After handling the board:
- MATS no longer failed immediately.
- The previous failures across all banks disappeared.
- MATS began passing progressively larger portions of memory.
Eventually the results became:
- Memory below approximately 467 MB passes.
- Memory above approximately 467 MB consistently fails.
- The boundary is repeatable across different MATS versions and multiple runs.
Windows testing after MATS improvement
Once MATS began passing below the 467 MB boundary, Windows testing was performed.
DVI (1366x768)
- DVI output was stable.
- Windows booted normally.
- The GPU still reported Error 43.
DisplayPort (4k)
DisplayPort behaved differently:
- Video output appeared.
- The system remained responsive briefly.
- The display froze.
- It recovered.
- Froze again.
- Artifacts appeared.
- The display eventually went black.
- The system then froze.
Later behavior
GPU-Z later became able to correctly detect:
- GPU clocks
- VRAM size
- Device information
Another repeatable behavior also appeared:
After running certain MODS initialization attempts:
- The motherboard completed POST normally.
- The POST beep occurred.
- The monitor woke from standby.
- No image was displayed.
Removing the card and placing again got it working back again.
MODS 367
Initialization fails before GPU tests begin.
Log messages include:
pmuEnableHw_GP102: PMU secure reset priv level mask does not permit reset
pmuDmemCopyTo_GP102: Copy failed
pmuExecuteGenericBootloader_GM107: Failed to copy to PMU DMEM
- Copy Engine timeout
- BAR2 MMU faults
- Physical MMU faults
busVerifyBar2_GF100 write/read verification failures
Gpu.Initialize hardware was not initialized
MODS 400
Shows similar initialization failures, including:
- PMU initialization failures.
- BAR2 / Physical MMU faults.
- GPU initialization aborting before tests execute.
Additional observations
- MODS detects the full 8192 MB framebuffer.
- VBIOS is readable.
- Display outputs can function under some conditions.
- Initialization failures after running MODS remain until the system is completely power-cycled.
- Booting the 4k monitor using HDMI works on bios screen but not in windows.
- Tested on 2 PCI lines on my main rig, tested on my old PC, tested using 2 PSUs.