Question about Radeon RX550 LP OC - 356863

I assume you mean the following model: support.apple.com/kb/sp589?locale=de_DE Apple has actually published a list of compatible GPU upgrades for this: support.apple.com/de-de/HT208898. Unfortunately, this graphics card is not listed as compatible. The compatibility requirements seem to be very specific according to my research: de.wikipedia.org/wiki/Mac_Pro#Grafik.