> the most intelligent think will be for me if they use the P5021 and not the P5020
> for have less problem?

The Cyrus Plus board with x4 x4 PCIe config as it is now is already configured optimally for the P5040 (and P5021). Using the P5021 instead of the P5020 would have brought no benefit except of a 2.2 GHz X5000/21 instead of the 2.0 GHz X5000/20. PCIe config would have been the same.

> or dont made the 5040 version and only 5020 and P3041 because are Pin compatible.

Indeed, the P3041 and the P5010/P5020 are both 100% pin-compatible and 100% SerDes config compatible. A board made for them (or just for P5010/P5020) would have meant no compromise in board design and SerDes lane assignment, allowing for x4 x4 x1 x1 PCIe config.

> P3041 plus is pin compatible with 4040 and 4080

P3041/P5010/P5020 are not more compatible with P4040/P4080 than with P5021/P5040 (which doesn't mean the last two groups are more compatible with one another, just in case someone might hit on this idea).