There are 2 ways Orion displays the bandwidth. Either it gets the information from the bandwidth statement on the interface's configureation, or you manually set it yourself on the GUI for the interface in Solarwinds (others have outlined the process above).
Please check those 2 settings.
Here's an example of where the interface has used the bandwidth statement from the interface's configuration to set the speed in the Solarwinds GUI.
If you want to manually set it to something else, tick the Custom Bandwidth box and fill out the details.