Both types write data synchronously into the RAM. Distributed RAM and dedicated block RAM differ primarily in how they read data. See the following table.
| Action | Distributed RAM | Dedicated Block RAM |
|---|---|---|
| Write | Synchronous | Synchronous |
| Read | Asynchronous | Synchronous |
Tool can choose between distributed RAM and dedicated block RAM based on the
RAM characteristics described in the HDL source code. Also, weigh the availability of
block RAM resources and whether you enforced an implementation style with the RAM_STYLE attribute.