There is No 4x25G listed for R550    i suggest to go for 2x Dual PCi if you have slots available. [IMAGE]  
Hi   We need to add a quad port network card 25GB SFP to a Poweredge R550. We are thinking of purchasing the below from Dell however the R550 is not in this compatible list. Can you please advise and if not compatible, what options to we have?   [URL]#compatibility_section
Poweredge R550 network Card