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

3.2.3. Target NoC Bandwidth

NoC targets are the bridges between AXI4 subordinate EMIF or HBM2E IP in the periphery, and the hard memory NoC. The number of NoC targets in your design and their associated bandwidth depends on the type of memory resource that your design uses. A NoC target is always connected to a specific memory controller, and the NoC target's location relative to the memory controller is always fixed.

The EMIF target operating frequency changes with memory protocol, memory frequency, and device speed grade, as External Memory Interface Target Frequency shows.

Table 6.  External Memory Interface Target Frequency
Device Speed Grade DDR4 Single TNIU Maximum Frequency (MHz) DDR5 Single TNIU Maximum Frequency (MHz) LPDDR5 Single TNIU Maximum Frequency (MHz)
-1 800 700 687.5
-2 800 700 687.5
-3 666.5 600 600

For DDR4 memory, the TNIU bandwidth exceeds the memory bandwidth for all speed grades. This means that if you use the full TNIU bandwidth, backpressure occurs on the NoC. The maximum data rate for DDR4 is 3200 Mbps. This maximum data rate means that the maximum bandwidth that DDR4 can accommodate is 3200Mbps x 32b= = 12.8 GBps. In contrast, the TNIU bandwidth is 25.6 GBps, which is double the bandwidth of the DDR4 memory.

HBM2E Target Frequency shows the fixed operating frequency of the HBM2E target for a given memory protocol and device speed grade.

Table 7.  HBM2E Target Frequency
Device Speed Grade HBM2E Single TNIU Frequency (MHz)
-1 800
-2 700
-3 500

The following equation applies:

Where:

  • Target Data Width = 256 bit or 32B
  • TNIU Frequency = refer to listed frequency per device speed grade in HBM2E Target Frequency

On a -2 speed grade device, you can expect to achieve a maximum bandwidth of 22.4 GBps per single EMIF DDR5 target and single HBM2E pseudo channel target running at 700Mhz.