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394 Views
Registered: ‎09-13-2019

Motherboard selection for PCIe with large BAR

I am working on a ultrascale+ with HBM2 design and want to make the full 8GB available to the host. Most motherboards are limited to a 32b address space and will not be able to support this.

How can I identify motherboards that support accessing the full 8GB?

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Xilinx Employee
Xilinx Employee
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Registered: ‎08-06-2008

Don't have much information on this. There is 'Above 4G Decoding' option in the BIOS in some systems. If that is enabled, you should be able to access larger memory. Did a quick search in google, looks like there are some additional information on this.

Thanks.

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Participant
Participant
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Registered: ‎01-27-2017

Hello there,

If you wish to memory map a huge amount of memory on your PCIe, you have to:

  • Enable UEFI
  • Enable 4G Above decoding in your BIOS (As previously mentioned by @deepeshm,)
  • Install your OS with UEFI
  • You may also need to add "pci=nocrs" to grub

All motherboards since many years support it.

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