Hi, which tansreciver to use? It does not depend on the server models but whether it has a NIC connected. You can use either 25G/40G  NIC to your R900.R900 supports I/O Slots Seven available PCI Express™ slots (four x8, three x4). Hope this helps and have a great one.
Hi guys not shure if this has been asked before, but we have a small project... and we have plans to try a pci-e 25G sfp transceiver or 40g but i am not sure where even to start with... can anyone confirm if dell supports a 25G or 40G QSFP transceivers for uplink... or its maximum limit is the SFP+ 10G ?   We are developing an SEBA/CORD opensource project and we have plans to put minimum a 25G transceiver for uplink and PON GBIC olt 10g sfp+.... 
PowerEdge R900 25G or 40G transceivers