AN 708: Application Note - PCI Express DMA Reference Design Using External Memory

ID 683390
Date 5/17/2017
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Throughput for Posted Writes

The theoretical maximum throughput is calculated using the following formula:

Throughput  = payload size / (payload size + overhead)
Figure 5. Maximum Throughput for Memory Writes The graph shows the maximum throughput with different TLP header and payload sizes. The DLLPs and PLPs are excluded from this calculation. Based on the graph, the theoretical maximum throughput on a Gen3 x8 link for a 3-dword posted write and no ECRC is 89.8%. The maximum throughput is 8 GBps x 89.8% = 7.19 GBps.