Inspiron 15 5510 performance issue

I discovered something odd about the performance of the Inspiron 15 5510 with i5 11300H processor and XM450 GPU. The problem presents when you configure in Ultra performance (other settings present almost the same behavior), when you start the system from shutdown, the performance of the laptop is not consistent and if you use a program like HWinfo64 to see the loading of the processor, you can notice in Cinebench 23 or other burning test software, the processor turbo a few seconds that can go from 22 to 26W, but the rest of the benchmark remains between 10 to 11W. This makes the overall result almost inferior to the Core i5 8250U. To resolve the inconsistency, you can disable the fast startup or restart the system without shutting down. This process make new benchmark or burning test remains between 18 to 26 watts throughout the process and the performance would be around +50% faster than the old Core i5.
In addition to the problem mentioned above, if the system is not restarted or disabled the Fast Startup, when there are heavy reads on the disk, it can lower the performance and also saturate the whole system.
I have contacted Dell service about this issue, but the staff only mentions that, if the system works, it is not a failure, but what I insist is that if the performance is not constant or it is not enough, then the experience would be awful. That is why I ask all the users who have this model if you can verify if the problem is consistent and report to Dell

The test was done from the original OS that came with the laptop and done the recovery and also a newly installed Windows 11. I don´t know if Dell is verifying this issue because the personnel that I talked to seems kind of annoyed by me....