Sudden jumps in temperature of the video card, what to do?

Question

Video cards

I have an old gigabyte gtx 470 with a turbine fan. I start the computer, immediately a wild fan noise (5000 rpm showed in gpu-z) At the same time, the gpu temperature, both in the gpu-z program and in msi afterburner, jumps very strange. First 64°, immediately 128, then something else, and back down. Literally every second a new temperature. Bios updated to the latest version, did not help. Please tell me what to do.

Answer 1

The program that monitors the temperature is buggy.
And the maximum overclocking of coolers at startup is the norm for some motherboards.