What the windows max pcie card bar size?

Question

I studied the PCIe Base Address Register(BAR) which can configurated as 32bits or 64bit. Therefore, I combined two BAR as one that BAR size defines as 256GB. But windows 10 can not allocate space for this pcie card(using x86_64 amd cpu as host). If there's no chance to defines size over 256GB, could someone can tell me the max pcie BAR size in Windows 10. Thanks.

Answer 1

Hello @GB

The technical limit for Windows 10 is 8TB as seen here: https://learn.microsoft.com/en-us/windows/win32/memory/memory-limits-for-windows-releases?redirectedfrom=MSDN

But, It's entirely possible that this is a limitation in your BIOS or your PCIe root complex. The BIOS does BAR assignments at boot time. Do you have a relatively high-end motherboard, or is it a cheap one? Do you know which chipset it uses? I don't know how many BIOSes can assign physical address ranges outside of the "PCIe hole" below 4GB.

Hope this helps with your query,

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