FAQ
TL;DR: 75 W from a PCIe x16 slot; "up to 75 W". If your PC won’t power on after adding a GPU, suspect a short or PSU protection; test the card in another PC and check cooler clearance/BIOS primary display. [PCI Express Card Electromechanical Specification]
Why it matters: This helps DIY PC builders quickly isolate no‑power faults after a GPU install without unnecessary part swaps.
Quick Facts
- Case study hardware: GTX 1050 Ti + i7‑3770 on MSI H61M‑P31(G3) with XFX Core XT 400 W PSU. [Elektroda, Durmond, post #18692177]
- Symptom observed: with GPU in PCIe, PC would not start; without it, the system booted and displayed. [Elektroda, Durmond, post #18692442]
- PSUs with short‑circuit protection may refuse to start when a GPU is shorted. [Elektroda, icey33, post #18692449]
- Root cause in this thread: cooler contact damaged the GPU; replacement resolved the issue. [Elektroda, Durmond, post #18695675]
- After a CMOS reset, BIOS defaults video to the integrated graphics. [Elektroda, mariuszp19, post #18692307]
Why does my PC refuse to power on after inserting a graphics card?
This behavior points to a short on the GPU or PCIe slot, triggering PSU short‑circuit protection. In that mode, the PSU can shut down instantly and fans may not twitch. Test the GPU in another system and inspect the slot. As one expert put it, "the power supply will not move with the card in the slot." [Elektroda, icey33, post #18692449]
How can I confirm if the graphics card itself is shorted?
Move the card to a known‑good PC and see if it powers on. Inspect the card for scuffs or burn marks near traces and mounting edges. Look for any area that may have contacted a metal cooler. As reported, "the aluminum part of the cooler touched the track on the graphics card and it burned." [Elektroda, icey33, post #18692436]
My PC works on the integrated GPU but won’t start with the dGPU installed. What does that indicate?
Integrated graphics working confirms the CPU, RAM, and PSU can boot. Failing to power on with the discrete GPU seated indicates a fault with the GPU or the PCIe slot. Remove the card and the system should boot normally, as observed in the thread. [Elektroda, Durmond, post #18692442]
Do I need to move the monitor cable when I add a graphics card?
Yes. Connect the monitor to the ports on the installed graphics card. If you leave the cable on the motherboard video output, you may see no image even if the system boots. Switch to the GPU’s HDMI/DP/DVI outputs for display. [Elektroda, mariuszp19, post #18692224]
Which BIOS setting should I check after clearing CMOS?
After a reset, many boards select the integrated GPU as the default display. Change Primary Display/Init Display First to PEG/PCI‑E in BIOS. As a reminder, "After a reset, the BIOS sets the integrated card as the default." Save and reboot. [Elektroda, mariuszp19, post #18692307]
Can a CPU cooler touching the GPU really kill the card?
Yes. Physical contact can bridge traces and cause a short, damaging the board. This thread’s failure followed cooler contact near the GPU. Quote: "the aluminum part of the cooler touched the track on the graphics card and it burned." Ensure clearance and add insulation if needed. [Elektroda, icey33, post #18692436]
How much power can a PCIe x16 slot supply to a graphics card?
A PCIe x16 slot supplies up to 75 W to a card. Higher‑power cards use 6‑pin or 8‑pin connectors for additional power. This matters when sizing PSUs and diagnosing no‑power faults after GPU installs. [PCI Express Card Electromechanical Specification]
Could the motherboard’s PCIe slot be the problem, not the GPU?
Yes. A damaged slot can short or fail to initialize. Cross‑test: try the suspect GPU in another PC, and a known‑good GPU in your board. "You need to test the card in another computer." This isolates the faulty component quickly. [Elektroda, krzychupar, post #18692444]
Fans spin only when the GPU is powered but not seated—what does that suggest?
If the system powers with the GPU powered but not in the slot, yet won’t start when fully seated, the PCIe interface path is shorting. That points to a bad card or damaged slot, not an overloaded PSU. [Elektroda, Durmond, post #18692442]
What was the final fix in this case?
The graphics card was damaged by cooler contact and had to be replaced. After replacement, the system powered on normally. This confirms the GPU was the fault, not the PSU or motherboard. [Elektroda, Durmond, post #18695675]
How do I avoid shorts when installing a large CPU cooler near a GPU?
Check for mechanical clearance around the PCIe slot before tightening. Keep metal fins or brackets from touching the GPU. Add insulating spacers or edge guards if tolerances are tight. This thread shows direct metal contact burned a trace. [Elektroda, icey33, post #18692436]
How do I troubleshoot a no‑power PC after installing a GPU? (3‑step checklist)
- Test the GPU in a known‑good PC to see if it powers on.
- Test a known‑good GPU in your PC’s PCIe slot.
- Inspect for physical contact, bent slot pins, or scorch marks before re‑seating.
[Elektroda, krzychupar, post #18692444]
