关于Vivado DDR3 IP向导新增的Number of bank machines选项

Number of Bank Machines:
DDR3 IP设置中会要求设置ddr3的bank数量，让人困惑的是此前已经选择了确定的器件，bank数量是固定的，为什么这里让选择bank的数量呢？
Xilinx官网有一条类似的问题被解决：
提问者：
I’m designing with the DDR3 IP core and using the Wizard to configure the memory.
I have selected the Memory Type = SODIMM and have supplied the memory part number.
One of the Wizard page ask to define the “Number of BANK machine”
Is this the same as the Bank address for the DDR3? If my DDR3 SODIMM datasheet has defined bank address(2:0)
then should I select from the Wizard for “Number of Bank Address” = 8 ?
Since the memory Part# is supplied to the Wizard already, why do I have to supply this Number of Bank Address?
Or is the Wizard asking for something else instead, seem like it means something else and not referring to the Bank address, not sure… …confusing.
官网回答：
Yes, the number of Bank Machines corresponds to the banks of the DDR3 device.
The IP usually defaults to 4 for larger devices and sometimes less for smaller devices. The reason it defaults to 4 is because adding more bank machines uses more FPGA resources which means you could have issues fitting the design and closing timing depending on your device and how full it is. For most applications users are able to high performance out of the MIG with 4 bank machines when they consider how to efficiently address the MIG through the app_addr and the “Memory Address Mapping Selection.” Some users may have a more bursty and random access pattern where they could see efficiency improvements with more bank machines, but other times some customers see no benefit from more bank machines but used more FPGA resources and didn’t see any benefit. My recommendation is to run simulations to see if you need or benefit from more bank machines.
UG586 talks about this starting on page 123.

可以看出这个选项的目的是为了使用ddr3ip时节省FPGA的资源。
更多信息可以查看原对话：
地址为
https://forums.xilinx.com/t5/Memory-Interfaces-and-NoC/DDR3-IP-Number-of-Bank-Machine/m-p/900013