Data said:
Hi,
I didn't just buy any ole RAM and stick it in the system. I made sure I had
the correct type (DDR DIMM), and was compatible with the right speed and type
(PC-3200) before I purchased the RAM. I also checked on crucial.com to
make sure I had got the correct type. Also, the fact that it is showing more
RAM than before would have to be due to the fact that the new module is at
least partially working.
I would also like to thank everyone for their help so far.
The Crucial scanner may have looked at the individual SPD chips on the
DIMMs. So it may not actually be using system level information (from
the OS), but looking at a level that at this point, doesn't matter.
The BIOS does two kinds of checks. The BIOS reads the SPD on
each DIMM, and plans the memory map, timings and clocks, according
to what it finds. But the BIOS also seems to use the old-fashioned
binary search, where it searches for the end of RAM, to figure out
the true size of the stick.
That is how, when a stick with a badly programmed SPD chip is used,
the BIOS still figures out the correct amount of RAM. For example,
if a 512MB DIMM has a 1GB SPD chip, the BIOS can still figure out
the stick is actually 512MB.
I'm trusting in this case, that the BIOS is currently the best
arbiter of what total size is present. The BIOS sets up the
initial address map, so the OS doesn't get a say in it. The
OS can have further restrictions (like MAXMEM), but the OS
shouldn't be able to declare more RAM than is actually
physically present.
With regard to memtest, I think that is still a test you should
pursue. It is the smallest download of an "alternate OS" you can
get, that will give some feedback on how much memory is present.
Unzipping this, should give a ISO9660 file (ending in .iso).
http://www.memtest.org/download/2.01/memtest86+-2.01.iso.zip
If you've downloaded an ISO9660 file from the web site, then you
need a burning program that knows how to move that information
onto the CD. It is *not* a matter of just burning the file to
the CD, with the WinXP built-in burning option. You do not want
to be able to look at the CD in explorer, and see blah.iso sitting
there all by itself. Instead, when proper burning is done, there
might be something like a single README.txt, while the actual
bootable test program is invisible. (The README was put there,
to tell you what is going on, with respect to the file system,
when proper burning is done. There is in fact, no need for a
README or even a file system to be present, but the burnmeister
who made the ISO wanted customers to have a warm fuzzy feeling.)
Readme.txt contents...
"There is no visible file here.
Memtest86+ is located on the bootsector of this CD.
Just boot from this CD and Memtest86+ will launch."
If you see that file on the burned CD, you did it right.
I burned my CD with a copy of Nero. You want any burning
tool that knows what to do with an ISO9660 file. If you
want a free tool, there is Deepburner Free, but this is
one I haven't tried. Check CDFreaks.com or cdrinfo.com for
comments or feedback about this program.
http://www.deepburner.com/?r=products&pr=deepburner&prr=features
When memtest86+ starts, you should see mention of the total detected memory
(as passed to memtest by the BIOS). As far as memtest is concerned,
there is the memory that is testable (what it declares), plus the
reserved memory that it cannot touch. The reserved area should be pretty
small, unless perhaps you have integrated graphics.
http://www.memtest.org/pics/nf2-big.gif
I didn't mention integrated graphics as a possible cause of the missing
memory in your case, because I cannot imagine 512MB allocated to a
built-in graphics function. But maybe you can set it that high in
the BIOS. If you are relying on integrated graphics, you can check
the BIOS and see whether an abnormally large allocation is being
used. But that would likely be reflected in what you see in
memtest, as an abnormally large reserved area.
Just a guess,
Paul
