AMD Ryzen7 5800X poor Cinebench results even with good AIO cooling

I just bought an Arctic Cooling Liquid Freezer III 280 for my Ryzen 7 setup because with my old cooler CPU temperature was at 90°C even at idle and I had major throttling issues. Now with the new cooler I have temperatures below 70°C even on full load while running Cinebench, but the Cinebench score is way below what I expected: I get only between 5-600 instead of the 800+ this processor is supposed to be capable of (according to Cinebench itself). [https://i.imgur.com/1FXnjvS.png](https://i.imgur.com/1FXnjvS.png) Is it possible that the excessive temperature with the old cooler damaged the processor, or could it just be a setup problem? Where do I start troubleshooting this?