Improve WPF DataGrid performance

There are a few options you can turn on to help you on your DataGrid object

EnableColumnVirtualization = true
EnableRowVirtualization = true

These two are the main ones I think might help. Next try making your binding async

ItemsSource="{Binding MyStuff, IsAsync=True}"

And lastly, I've heard that setting a maximum height and width can help even if it above the max screen size, but I didn't notice a difference myself (claim had to do with auto size measuring)

MaxWidth="2560"
MaxHeight="1600"

Also never put a DataGrid in a ScrollViewer, because you will essentially lose virtualization. Let me know if this helps!

Check if you have property ScrollViewer.CanContentScroll set False. Setting this property to false disables the virtualization in a way will degrade the performance of your Data-grid. For more clarification refer this CanContentScroll