I upgraded my graphics card from an RTX 3060 Ti 8GB to an RTX 5070 Ti 16GB. Before installing it, I cleaned the inside of the computer and removed the CPU cooler to redo the thermal paste. After reconnecting everything, the PC shows no signs of powering on. I checked the connections several times and tried starting it with both the new card, the old card, and no GPU installed, but nothing changed. The system uses a Corsair RM750 power supply, and the GPU power cables are daisy-chained. Could that be preventing the computer from starting, or might I have disturbed another connection while cleaning and repasting the CPU?
4 Answers
When you redid the thermal paste, did you remove the CPU from its socket, or only take off the cooler? If the CPU was removed, inspect the socket and processor for bent pins or poor seating. If only the cooler was removed, make sure it isn’t overtightened and that the CPU power lead was reconnected.
Put the old card back in and carefully inspect every connection you may have disturbed while cleaning. Pay particular attention to the 24-pin motherboard connector, the CPU power cable at the top-left of the board, the front-panel power-switch connector, and any loose wires. Testing one change at a time makes it much easier to identify what went wrong.
Start with the basics: check that the power supply switch is set to on and that the AC cable is firmly connected. Since the computer also fails to start without a graphics card installed, the new GPU probably isn’t the only issue.
An RM750 should generally be enough for this setup, and a daisy-chained PCIe cable is unlikely to explain a complete lack of power. Using separate PCIe cables is still the preferred approach when possible, but first focus on the motherboard, CPU power, and case power-switch connections.
I tried starting it with and without both graphics cards, but it still showed no response. I’ll go back over the motherboard and front-panel connections again.