I can confirm that latest 2301 BIOS is performing noticeably worse than previous 2203. I didn't follow the rule "If it ain't broke, don't fix it" and it cost me over 2 hours of troubleshooting, restoring settings and a BSOD in the middle of a game session. Right after upgrading to 2301 I replicated my settings from previous version by copying everything 1:1 using screenshots taken right before upgrading. That means there is literally no difference other than the upgrade itself. My system is equipped with Core i9-9900K cooled by Noctua NH-D15 so there is no hardware bottleneck whatsoever. What's wrong with the latest BIOS version?
1. CPU power draw under synthetic AVX load has gone up by 7-10% (10-15W) with the same frequency - 4.8 GHz across all cores with AVX offset at "0". On 2203 and earlier I was using CPU Vcore offset -0.020v, after upgrading I couldn't make my system fully stable until I set Vcore offset to +0.020. That adjustment changed VID voltage (highest value) from 1.215v to 1.219v with occasional spikes to 1.221v. If I set the voltage any lower than that, I was getting random BSODs (including the one I had during gameplay).
2. Cinebench R20 multi-core score has dropped by 100 points (from 5080 to ~4980). Combine that with my previous point about higher power draw at the same clocks and it looks really disappointing. I've ran multiple tests on 2301 with consistent results, then downgraded to 2203, restored BIOS settings from file (luckily I had backups) and then reran the same test many times to confirm my statement (with positive result).
So if you are running on 2203, don't upgrade unless you have some unresolved issues which may get fixed in the latest release. But if everything works fine, don't touch it! You can only make things worse, just like I did. And at the end of the day, I reverted back to 2203 and promised myself to not touch it unless it is really necessary.
Hope it was helpful!