Errors in RAM reported by Belarc Advisor and SiW

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Working on a friend's computer (NEXlink with a Foxconn motherboard,
Model NF4(X)K8MC-ERS), I was puzzled to see that both Belarc Advisor
and System Information for Windows show 4 memory slots, but there are
only two on the board.

Further, of the two slots, one is empty and the chip in the other is
labeled 1024MB-PC400KIT.  However, both SiW and Belarc, as well as
System Properties of the Control Panel, show 512 MB of RAM installed
in the one slot.

In hunting for new RAM to install, I had trouble identifying the exact
motherboard model.  Finally I turned the computer on its side and,
while typing up this post, idly glanced at the system unit. On the
bottom panel was a label with the complete motherboard model number.
The utilities I have been using only left off the -ERS suffix.   Oh,
and, yes, sometimes this motherboard is described as nF4K8MC, without
the (X).

Is there an explanation other than that these free utilities are
perhaps flawed?

Is there a BIOS or other setting that limits the amount of RAM
recognized by the OS (running Win XP Home SP2 fully upgraded)?

Any help will be appreciated.

Bob Stromberg in Greenwich, NY

Re: Errors in RAM reported by Belarc Advisor and SiW wrote:
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There wouldn't be a BIOS setting to exclude memory, but that leads me to
ask what does the BIOS say about the installed memory. If the BIOS says
512MB then the DIMM is either defective or the module needs to be
reseated or cleaned.

Re: Errors in RAM reported by Belarc Advisor and SiW wrote:
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The utilities are doing the best they can, with the available information.

On the chipset itself, any utility can see there are four interfaces
for RAM. So that looks like four sockets to them. But the motherboard
design, does not have to connect DIMM sockets, to each of the interfaces.
(So scanning the Northbridge, you'd find four interfaces, but I don't think
there is a way to tell a socket is connected to it.)

When a DIMM is installed, each DIMM is supposed to have an SPD chip on
it. The chip is a serial EEPROM, and stores timing numbers and if you
are lucky, the memory also has a serial number. In that case, each DIMM
can present a unique ID, and be properly noted by the OS or any utility
that cares to look in the right place. So once a DIMM is inserted,
for the most part, it should be detectable, in the "present and accounted
for" sense.

Now, another information facility on the motherboard, is called DMI. There
is actually a spec that defines DMI (I believe the spec is now defunct and
is no longer in force). In any case, the DMI is a section of the BIOS chip,
and is updated by the BIOS during POST, as a function of new hardware
that is detected. So when you plug a DIMM in, the BIOS updates the DMI
table area of the BIOS flash chip, with the info for the new chip. If you
later remove the DIMM, the DMI area is again updated to reflect the current

Some motherboard makers provide a "DMI Explorer" tool, for dumping the contents
of the DMI. On Asus, it is part of some other tool (Asus Probe? Not sure). I
expect, judging by the poor quality of info I see in some utilities, that those
utilities are dipping into that DMI information store as well.

The problem with DMI, is it is assembled by humans, and is prone to errors
of omission, and just plain carelessness. I can see, for example, that one
motherboard I've got, has "70ns memory" in it, which is something that
existed in another time (EDO/FPM memory). So the info in the DMI is only
as good as the BIOS designer, and since DMI doesn't sell products, and
only sucks up designer resources, you aren't likely to see it raised to a
high priority in BIOS updates. Maybe they'd spend more time getting it
right on a server motherboard.

Some of the utilities, are populated with info by the utility designer.
So as soon as they see the motherboard model number, they simply dump
a table of static information stored inside the utility. That is another
way to solve the problem, by simply avoiding the DMI.

As for the identify of the motherboard, there are probably a couple strings
inside the BIOS chip, that identify it. I think the BIOS themselves are
supposed to be registered, and the "BIOS String" is something that people
use to figure out what they've got. In addition, there are also smaller
8 character fields, that might attempt to make the BIOS unique enough, that
a flashing tool can compare the new BIOS file, to the one that is currently
in the machine.

Example of BIOS string:

BIOS String on my computer:

So, for the most part, the DMI info that is stored in the BIOS, should not
be regarded as being very reliable. The things that are important to make
the machine work (each DIMM has SPD and probing serial bus finds them)
are bound to work right, or the tech support phone calls would be endless.
But I doubt a lot of people phone up to complain about the DMI, because
anybody who really cares about hardware inventory, would use something
other than the DMI as their information source.

1024MB-PC400KIT :-) That looks like somebody opened up a package
containing 2x512MB DIMMs (a "kit" for dual channel applications),
and only installed one of them in the computer. So, if you had
possessed the original package the RAM came in, you'd see that
the DIMMs were 512MB each. The labeling is a bit deceptive, because
it is only correct labeling, if you still have both sticks.

As for Foxconn, their naming scheme boggles the mind. It is best,
when a motherboard limits its name to 8 characters, because then
the odds are better that all tools will properly identify it. If
the name is too long, then it'll get truncated.

As for WinXP, just throw the RAM into the computer. You shouldn't
have problems like you might have had with Win98. If there is too
much RAM, the OS just throws it away :-) If you want, you could use
2x1024MB of memory, in your two available slots. That is the best
compromise amount of RAM right now, because you'll get to use
all of it with a 32 bit OS.

You can look up the motherboard on the Crucial or Kingston sites,
to get some info on what will fit in the board.

For some nice RAM (CAS2 low latency), there is this stuff I saw yesterday.
Back in stock on Oct26.

The only thing I don't recommend, is buying 1GB DDR memory from Ebay.
You can buy anything else (512MB DDR, 1GB DDR2, 512MB DDR2 etc), but
there is a particularly cheap and nasty 1GB DDR they sell on Ebay
that I don't recommend. Usually the advert mentions a "restricted
set of chipsets" it works with, and for all the trouble this causes,
just stay away from Ebay if you want a 1GB DDR memory DIMM. There is
likely a cheaper RAM product on Newegg -- just read the reviews to
avoid stuff with excessive DOA reports.


Re: Errors in RAM reported by Belarc Advisor and SiW

Thanks, Pen, Paul, and Mike, for the answers.  I understand much
better what my choices are.


Re: Errors in RAM reported by Belarc Advisor and SiW

The limit on the amount of memory is the physical limitation of the motherboard.
The most common problem is that there is a limit to the size of memory chips
(number of bits) that can be addressed. If the chip density is higher than the
motherboard supports you might be able to address only half of the chips
capacity. Usually a DIMM with more lower density chips instead of fewer higher
density chips will work properly. E.g. try a DIMM with 16 chips instead of 4 or
8 chips. wrote:
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