[LBo] Memory

[Troy]

Hi all.  The manual (rev:1.02) for my motherboard (ABIT BH6) states the
maximum amount of memory is 384 MB.  However, for the past year I've been
running 400 and some MB - I'm having a difficult time determining exactly
how much memory I have.  The bios shows 424,960k, and when the computer is
first turned on, the memory count is 425,984k; I believe the difference is
the 640k base and 384k other that is stated in the bios.   When I enter free
at the cli, I'm told I have 418,372k.  Any ideas as to why I have different
amounts of memory being reported?

Back to my question about the maximum amount of memory.  I found another
manual for my motherboard online (rev: 1.06) that states the maximum amount
of memory is 768MB.  Being the online manual states 768MB as the maximum and
I'm already running 400 and some MB just fine, do you think I'm safe in
purchasing more memory and maxing out the memory at 768MB?

Other information is the memory type is 168-pin DIMM SDRAM.  Someone told me
I need to pay attention to high density and low density?

Thanks,

Troy