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i just read a paper named Memory Hole in Large Memory X86 Based Systems
They decribe the device memory & physical memory conflict described in this thread. However, i don't think i'm properly understanding what the PCI hole is. There's a pic in there describing a memory map of a computer with 1gb of ram. It shows that the device memory is always set with the highest address at the 4gb limit. I guess device memory uses these addresses to avoid conflict with physical memory. but they go on to say
they say the reason is because the bios always loads device memory at the 4gb edge regardless of what cpu or OS you are running
They decribe the device memory & physical memory conflict described in this thread. However, i don't think i'm properly understanding what the PCI hole is. There's a pic in there describing a memory map of a computer with 1gb of ram. It shows that the device memory is always set with the highest address at the 4gb limit. I guess device memory uses these addresses to avoid conflict with physical memory. but they go on to say
This rest of paper further explores the memory hole and other related issues. It also explores the reasons why a 64-bit processor and a 64-bit operating system won't simply fix this problem.
Before we explore the details for the apparent missing memory, let's take a look at the problems associated with breaking the 4 GB limit. First, let's do a little review of the basics.
they say the reason is because the bios always loads device memory at the 4gb edge regardless of what cpu or OS you are running