I upgraded my graphics card from an RTX 3060 Ti 8GB to an RTX 5070 Ti 16GB, cleaned the inside of the computer, and replaced the CPU thermal paste during the same maintenance session. After reconnecting everything, the computer shows no signs of powering on. I've checked the connections several times and confirmed that the components should be compatible. The only possible concern I can think of is that the GPU power cables are daisy-chained. My power supply is a Corsair RM750. I've tried starting the system with both the new and old graphics cards, as well as with no graphics card installed, but nothing happens. What should I check next?
4 Answers
If removing and reinstalling the CPU was part of the thermal-paste work, inspect the socket and CPU carefully for any seating or contact problem. If you only removed the cooler and left the CPU installed, that is less likely to be relevant. Also confirm that the cooler was reinstalled evenly and its fan is connected, although a cooler issue would more commonly cause a shutdown after powering on rather than no response at all.
Try putting the original GPU back in and inspect every cable after the cleaning. Make sure the CPU cooler is connected to the CPU_FAN header and that no wire is trapped or partially disconnected. Also check that the RAM is fully clicked into place. For troubleshooting, change only one component or connection at a time so it’s easier to identify what caused the failure.
Since the system also fails to start with the old card or with no GPU installed, the graphics card probably isn’t the main issue. Recheck the basic power connections first: make sure the PSU switch is on, the 24-pin motherboard cable and the CPU power cable near the top-left of the motherboard are fully seated, and the front-panel power-switch connector is still attached correctly. Cleaning and cable management can easily knock one of those loose.
A Corsair RM750 should generally provide enough power for this setup, and a properly connected daisy-chained PCIe cable would not normally prevent the computer from powering on. Using separate PCIe cables for the new GPU is still the preferred arrangement, but because the PC won’t start even without a GPU, focus first on the motherboard, CPU power, case switch, and PSU connections.
I already tried powering it on with the old card and with no card installed, and it behaved exactly the same. I’ll go back through the motherboard and front-panel connections again.