Not so much temperature as Temperature AND Frequency.
GPUs will boost as long as they have thermal and power headroom. A GPU operating at 75C running at base clocks or lower is still overheating or has other issues. If you see high frequencies like 2800-3000Mhz then the GPU is doing what it is supposed to do.
Typical Nvidia stock target is 83C. Other vendors can and do set lower/higher limits and these can be adjusted via software. MSI Afterburner being the most common. This will also allow for custom fan curves.