Greetings peteryouhannafawzy ,
according to the Datasheet and the information of this device SG550XG-24T-K9-EU, it can work to 1Gbps but it's going to depend about SFP module.
Please, use this URL to look more information about this device SG550XG Datasheet and lookup the information of Supported SFP/SFP+ modules.
If you need more information, please, let us know.
Mario Espinoza
.:|:.:|:. Cisco Small Business TAC
Email: marioesp@cisco.com
Shift Hours: Monday - Friday from 9:30 AM – 7:00 PM (EST)
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