Some close-up pictures of these two varieties growing in the same conditions – light, temperature, etc.
Unknown (left) and “Prince Philip” (right). As you can see they are quite different.
Sergey -
Your unknown looks similar to Albicans which has not been a real strong grower for me.
Pic in upper right shows a recent Albicans air layer next to a Prince Philip. The other 3 pics are of Albicans. The yellow in Albicans fades to a creamy white on the older leaves; Prince Philip stays yellow.