You can configure block RAM resources to provide the following synchronization modes for a given read/write port:
•Read-first: Old content is read before new content is loaded.
•Write-first: New content is immediately made available for reading Write-first is also known as read-through.
•No-change: Data output does not change as new content is loaded into RAM.
Vivado synthesis provides inference support for all of these synchronization modes. You can describe a different synchronization mode for each port of the RAM.