I recently bought a used **Gigabyte RTX 3070 Ti Vision**. After installing it and running some tests, it seemed to be working fine, though temperatures were hitting around **85°C**. I decided to take it apart to clean it and replace the thermal paste.

After the maintenance, I put it back together and it worked great at first—in-game temperatures dropped to around **65°C**. However, during a match, the PC suddenly shut down and now it won't turn back on.

**Symptoms:**

* When I try to power it on, the PC lights flash for a brief second and then everything goes dead.
* If I only plug **one** power cable into the GPU, the PC starts up (but obviously no video output).
* If I plug in **both** power cables, the LEDs just flicker once and nothing happens. On a second attempt immediately after, it doesn't even flicker.

**Current Status:** I removed the 3070 Ti and installed a **4060 Ti** instead, and the computer is working perfectly fine.

**My questions:**

1. Could it be that my PSU (Power Supply) simply can’t handle the 3070 Ti anymore?
2. What’s weird is that it worked for a while with great temperatures before dying. Could I have messed something up during the repasting process?

I'm using a **600W EVGA power supply** that is about **8 years old**. Could it be failing to handle the transient power spikes of the 3070 Ti, even though it runs the 4060 Ti fine?  
  
I’m really confused because the temps were much better after I cleaned it. Any advice on what to check next would be greatly appreciated!

PC shut down mid-game after GPU repaste – Won't turn back on with 3070 Ti installed. Help!