Intel® Hyperflex™ Architecture High-Performance Design Handbook

ID 683353
Date 10/04/2021

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Document Table of Contents Unregistered RAM Outputs

To achieve the highest performance, register the output of memory blocks before using the data in any combinational logic. Driving combinational logic directly, with unregistered memory outputs, can result in a critical chain with insufficient registers.

You can unknowingly use unregistered memory outputs, followed by combinational logic, if you implement a RAM using the read-during-write new data mode. The Compiler implements this mode with soft logic outside of the memory block that compares the read and write addresses. This mode muxes the write data straight to the output. If you want to achieve the highest performance, do not use the read-during-write new data mode.