405 g6 and CPU upgrade

[krake_n]

Hello
I am the owner of a prodesk 405 g6 with a 4650ge processor. I already wrote a post on upgrading the processor to 5650ge https://h30434.www3.hp.com/t5/Desktop-Hardware-and-Upgrade-Questions/405-g6-and-CPU-upgrade/m-p/8412...
I got the answer that cezanne is not supported even though agesa is the latest. after that I downloaded the latest bios and uploaded it to the Ryzen SMU Checker where I actually saw that HP removed the cezanne microcode from agesa. Only renoir is present. I do not see a technical justification for this, because the same 405 g8 has the same chipset and agesa, and this is just a marketing ploy to buy more recent model.
Then I decided to upgrade a processor from the renoir family, the choice fell on 4750ge, but it is not possible to find it, unlike 4750g, which was installed on the 805 g6 model. Before buying it, I downloaded bios 805 and 405 and checked them in Ryzen SMU Checker, they are identical in terms of microcode, which means 4750g should work on 405 g6 BUT ...
G and GE differ in tdp (35 vs 65), and just like that this processor will not work. I managed to find a heatsink from 805 g6 which is copper with tdp 65,  also I bought usb 90w type-c charger (there is a type-c board with a charging port), 90w is used in 805 g6 with non-GE processors and I also bought 4750g.
I installed 4750g and after turning it on, 3 long and 5 short beeps occur, which, as I understand it, stands for no processor detected. Then I returned the old processor and the BIOS was restored to factory settings. Then I checked 4750g on another non-hp computer - it works there.
You can of course say that here is a list of supported processors https://support.hp.com/us-en/product/hp-prodesk-405-g6-desktop-mini-pc/38255713/document/c06955645#A... , but Ryzen SMU Checker said that there is no microcode for picasso in the BIOS, and there is doubt that the 3400ge will work on 405 g6, which means there may be doubts that G series processors are not supported. Moreover, there is no fundamental difference in hardware with 805 g6.
Please tell me why 4750g can not work with 405 g6 with a new power supply and cooling system? Or is there a blacklist for processors in the BIOS? I don't see any technical limitations.

[BeemerBiker · Accepted solution]

The 4750g and 4750ge are both Renoir series processors.  I am going to guess that the HP board lacks the voltage regulation that can provide the correct voltage to operate the g series at the 65 watt level.

You might join the winraid forum and ask over there

https://winraid.level1techs.com/t/amd-ryzen-new-cpu-support-on-older-motherboards-and-agesa-porting/...

I ran into a similar problem trying to get a Xeon to work in a Dell 435mt where the CPU  worked in the 435t model.

Adding the missing microcode to the bios of the 435mt did not help as the motherboard did not have the required components