AN 1003: Multi Memory IP System Resource Planning: for Intel Agilex® 7 M-Series FPGAs

ID 788295
Date 11/22/2023
Public
Document Table of Contents

3.1.2. External Memory Interface Controller Efficiency

For each external memory interface in an Intel Agilex® 7 M-Series FPGA, the following equation calculates the ideal bandwidth that a memory can achieve, based on 100% controller efficiency:


EMIF Controller Preliminary Efficiency Data shows the typical efficiency for the External Memory Interface controller running at different memory frequencies across various protocols in an Intel Agilex® 7 M-Series FPGA. The data indicates sequential memory access has higher efficiency compared to random memory access.

Table 3.  EMIF Controller Preliminary Efficiency Data
EMIF Protocol Access Pattern Read (%) Write (%) Controller Efficiency (%)
DDR4 Sequential 100 0 >90%
Sequential 0 100 >90%
Random 100 0 >60%
Random 0 100 >60%
DDR5 Sequential 100 0 >90%
Sequential 0 100 >90%
Random 100 0 >70%
Random 0 100 >50%
LPDDR5 Sequential 100 0 >90%
Sequential 0 100 >90%
Random 100 0 >60%
Random 0 100 >60%

The per interface bandwidth of the external memory interface for an FPGA depends on the following factors:

  • Data rate per bit
  • Data bus width
  • Data bus efficiency (percentage of time data is actively being transferred)

The following equation expresses the total effective bandwidth per interface as a function of all these factors:



You must account for EMIF controller efficiency across various traffic scenarios, while determining overall system performance through Hard Memory NoC.