Comment on How is RAM size measured? Why doesn't it match the marketed size?
kbal@fedia.io 2 weeks ago
Maybe it's not counting memory that can't be tested because it's needed for the kernel and device drivers. For example according to its man page free reports total memory "memory minus a few reserved bits and kernel binary code" and on my desktop here that's about 15.5 out of 16GB.
zaphod@sopuli.xyz 2 weeks ago
There is no kernel and no device drivers, MemTest86+ runs on bare metal and it moves itself around to test all memory, so it uses virtually no memory and should show all available memory.