Have 8GB of RAM, but addresses of errors are out of that range?

[Dwedi]

I have 8GB of RAM in a computer, but Memtest86 is reporting errors at address 0020B9BF818, which is beyond 8GB. What does this mean?

[keith]

Even though your system may have 8GB of physical memory, the maximum system memory address may be greater than 8GB due to certain address ranges of the system memory being assigned to memory-mapped IO (MMIO), device memory, boot ROM, etc...

Because the system memory map not only includes physical memory but other devices, you may see an address value (slightly) greater than the physical RAM size.

Background information about memory mapped I/O