256 MB memory missing

  • Thread starter Thread starter baris.boyvat
  • Start date Start date
B

baris.boyvat

Hello,

I have two DDR DIMM slots on my motherboard and before I had
768 (512 + 256) MB memory with two memory modules. Everything
was fine at that time. Recently I bought a 1 GB DDR DIMM 400 MHz
memory module. My motherboard's manual tells that I can use up to
1 GB DDR DIMM in any slot. I should be free to use any slot as well.

Well, the problem is that when I put 1 GB memory to one slot and
used with 512 MB memory, but Windows (System Properties-General
& Task Manager) shows that I have only 1.25 GB so 256 MB
memory is somehow missing. In order to be sure that memory modules
are ok, I tried the 1 GB memory alone and 512 MB alone and there
weren't any problems. I also switched the slots I put them but I
again
had 1.25 GB. Does anyone know what the problem is? Thanks in advance.

Some additional information about my box. I have an AMD Athlon XP
2200+ CPU and a MSI KT6V (MS-7021 v1.X) ATX mainboard. The
KT6V mainboard is based on VIA KT600 North Bridge & VT8237
South Bridge chipset.

Cheers,
-Baris
 
Perhaps run MSconfig and check the "maxmem" setting under BOOT.INI,
"Advanced Options"
Click to expand...

Thanks for the suggestion. I tried it but it wasn't possible to set a
maxmem
value higher than 1280.

-Baris
 
Hello,

I have two DDR DIMM slots on my motherboard and before I had
768 (512 + 256) MB memory with two memory modules. Everything
was fine at that time. Recently I bought a 1 GB DDR DIMM 400 MHz
memory module. My motherboard's manual tells that I can use up to
1 GB DDR DIMM in any slot. I should be free to use any slot as well.

Well, the problem is that when I put 1 GB memory to one slot and
used with 512 MB memory, but Windows (System Properties-General
& Task Manager) shows that I have only 1.25 GB so 256 MB
memory is somehow missing. In order to be sure that memory modules
are ok, I tried the 1 GB memory alone and 512 MB alone and there
weren't any problems. I also switched the slots I put them but I
again
had 1.25 GB. Does anyone know what the problem is? Thanks in advance.

Some additional information about my box. I have an AMD Athlon XP
2200+ CPU and a MSI KT6V (MS-7021 v1.X) ATX mainboard. The
KT6V mainboard is based on VIA KT600 North Bridge & VT8237
South Bridge chipset.

Cheers,
-Baris
Click to expand...

If bought from Ebay, there are people selling "high density" RAM. The
(partially) honest sellers, include a list of "compatible" chipsets.
You can see KT600 is in the list in this example. Now, does that mean
you can use three sticks of that stuff ? Who knows...

http://cgi.ebay.com/1gig-ddr-high-d...133400254QQcmdZViewItem?hash=item290133400254

I would be using memtest86+ from memtest.org . The download will prepare
a bootable floppy or the ISO version makes a bootable CD. Memtest should
report the amount of memoty it sees, and test it for you.

http://www.memtest.org/pics/amd64-big.gif

I would do at least two complete passes with any potential memory
combination or single stick, until you are error free and happy with
the results. Booting into Windows with an unstable memory config, is
just asking for trouble.

Paul
 
I would be using memtest86+ from memtest.org . The download will prepare
a bootable floppy or the ISO version makes a bootable CD. Memtest should
report the amount of memoty it sees, and test it for you.
Click to expand...

memtest find 1280 memory as well. I tried to set the upper limit
higher but
it didn't work.

I wonder if there is a problem related to two different type of
memories working
together because separately they seem to work quite well. Both of them
are
DDR DIMMs but they would most probably differ in many other
parameters.

-Baris
 
memtest find 1280 memory as well. I tried to set the upper limit
higher but
it didn't work.

I wonder if there is a problem related to two different type of
memories working
together because separately they seem to work quite well. Both of them
are
DDR DIMMs but they would most probably differ in many other
parameters.

-Baris
Click to expand...

The addressing method used, should be independent in each slot. In other
words, the rows/columns/banks setting of the memory controller, should
be unique for each memory slot. They shouldn't interact.

What is shared between all slots, is choice of timing parameters and
clock rate. But timing parameters and clock rate don't affect memory size.

The BIOS has a couple ways to "size" the memory, and prepare the reserved
memory information to pass to memtest or to an OS. The SPD gives size
information, but I believe the detected memory size is also subject to
BIOS verification. Before there was SPD on DIMMs, the BIOS used to detect
memory size, by doing test writes and reads, and seeing whether the writes
were working or not. Thus, the BIOS could search, to see what the memory
size was. It could be that the BIOS is doing a step like that, and
for reasons unknown, is not getting reliable storage over the entire
physical memory.

This could even be a BIOS problem, in the sense that the Northbridge
memory controller has to be programmed, to map a physical address, to
a particular memory slot chip select. Maybe there is a problem there,
such that two sticks are responding to the same address (address overlap?).

Your options at this point, might be, to accept operation with a single
1GB stick, and use the 1GB of memory. (Test that it works well of course.)

Alternately, sell the 1GB high density stick, and buy a branded 1GB stick
from Kingston, Crucial etc, as branded memory will come in the
low density format. That is more likely to work, and work across
a wider range of motherboards.

The high density RAM is an approved format in JEDEC specifications, but
every Intel datasheet I've looked at, rejects it as a valid option. Intel
only wants to see x8 and x16 chips on unbuffered modules. It is for that
reason, that I will not personally be buying high density RAM from
Ebay, no matter what chipset my motherboard has.

Paul
 
Alternately, sell the 1GB high density stick, and buy a branded 1GB stick
from Kingston, Crucial etc, as branded memory will come in the
low density format. That is more likely to work, and work across
a wider range of motherboards.
Click to expand...

First of all thanks Paul for your support.

Actually now I've checked the 1GB module. It is Elixir
M2Y1G64DS8HB1G-5T. It has a sheet at
http://tinyurl.com/29ayf5. Briefly it is an "unbuffered
200-Pin Double Data Rate (DDR) Synchronous
DRAM Unbuffered Dual In-Line Memory Module (UDIMM)
and is organized as two ranks of 128Mbx64 high-speed
memory array using sixteen 64Mx8 DDR SDRAMs TSOP
packages". I bought the module from a big computer
shop and they sell this memory module with the shop's name
and it is the cheapest one. But on the memory it says Elixir.

Now I tried the 1 GB module with my 256 MB module and
then the computer doesn't even start up. But the 256 MB and
the 215 MB work fine together.

The 512 MB module is from Veritech. It is
VM512MBDDR400 PC400.

The 256 MB module is from Infineon. And it is DDR 333,
CL 2.5, ECC, 32Mx72. BTW this ECC might be a problem
as well because some webpages tell that my motherboard
doesn't support ECC. The 1GB module is for instance
non-ECC.

-Baris
 
Thanks for the suggestion. I tried it but it wasn't possible to set a
maxmem
value higher than 1280.

-Baris
Click to expand...

Unless you have a very good reason for doing so (and these reasons are
very rare) you should not have any value in the /MaxMem= line and the
checkbox for it should not be selected.

Good luck

Ron Martell Duncan B.C. Canada
--
Microsoft MVP (1997 - 2008)
On-Line Help Computer Service
http://onlinehelp.bc.ca
Syberfix Remote Computer Repair

"Anyone who thinks that they are too small to make a difference
has never been in bed with a mosquito."
 
Alternately, sell the 1GB high density stick, and buy a branded 1GB stick
from Kingston, Crucial etc, as branded memory will come in the
low density format. That is more likely to work, and work across
a wider range of motherboards.
Click to expand...

First of all thanks Paul for your support.

Actually now I've checked the 1GB module. It is Elixir
M2Y1G64DS8HB1G-5T. It has a sheet at
http://tinyurl.com/29ayf5. Briefly it is an "unbuffered
200-Pin Double Data Rate (DDR) Synchronous
DRAM Unbuffered Dual In-Line Memory Module (UDIMM)
and is organized as two ranks of 128Mbx64 high-speed
memory array using sixteen 64Mx8 DDR SDRAMs TSOP
packages". I bought the module from a big computer
shop and they sell this memory module with the shop's name
and it is the cheapest one. But on the memory it says Elixir.

Now I tried the 1 GB module with my 256 MB module and
then the computer doesn't even start up. But the 256 MB and
the 512 MB work fine together.

The 512 MB module is from Veritech. It is
VM512MBDDR400 PC400.

The 256 MB module is from Infineon. And it is DDR 333,
CL 2.5, ECC, 32Mx72. BTW this ECC might be a problem
as well because some webpages tell that my motherboard
doesn't support ECC. The 1GB module is for instance
non-ECC.

-Baris
 
First of all thanks Paul for your support.

Actually now I've checked the 1GB module. It is Elixir
M2Y1G64DS8HB1G-5T. It has a sheet at
http://tinyurl.com/29ayf5. Briefly it is an "unbuffered
200-Pin Double Data Rate (DDR) Synchronous
DRAM Unbuffered Dual In-Line Memory Module (UDIMM)
and is organized as two ranks of 128Mbx64 high-speed
memory array using sixteen 64Mx8 DDR SDRAMs TSOP
packages". I bought the module from a big computer
shop and they sell this memory module with the shop's name
and it is the cheapest one. But on the memory it says Elixir.

Now I tried the 1 GB module with my 256 MB module and
then the computer doesn't even start up. But the 256 MB and
the 215 MB work fine together.

The 512 MB module is from Veritech. It is
VM512MBDDR400 PC400.

The 256 MB module is from Infineon. And it is DDR 333,
CL 2.5, ECC, 32Mx72. BTW this ECC might be a problem
as well because some webpages tell that my motherboard
doesn't support ECC. The 1GB module is for instance
non-ECC.

-Baris
Click to expand...

Well, now I'm baffled.

Motherboard - KT600 based, with two DIMM slots only. The word
"ECC" does not appear in the manual, as a warning
or otherwise. The KT600 page on VIA.com.tw doesn't
mention the word ECC either.

512MB non-ECC + 256MB with-ECC = 768MB and it works.
1GB low density non-ECC + 512MB non-ECC = 1.25GB only reported, 256MB missing.
1GB low density non-ECC + 256MB with-ECC = Will not POST.

The fact that the first combination works, tells you that ECC
is a non-issue. If the ECC chip is undriven, that is not a
problem, in terms of system operation. The only risk is with
respect to the BIOS getting into trouble parsing the SPD
fields.

I've only got one suggest left. Have you tried swapping the
position of the modules, i.e. 1GB in slot1 and 512MB in slot2,
then 512MB in slot1 and 1GB in slot2 ? If the results are
different, perhaps one slot has a dirty pin that is not
making good contact. With enough insertion and removal
cycles, eventually you'll clean it off.

OK, I have a theory. Chip select is broken on one of the
slots, such that only one side of one of the slots
is addressable. This may become more apparent, if you
compare 512MB + 256MB config, versus 256MB + 512MB. In
other words, try both possible slot combinations for the
originally working 512 + 256 sticks. If one combination
reports 512MB total and the other reports 768MB total,
then the chip select pin on the slot with the 512MB is
dirty.

Paul
 
Well, now I'm baffled.
Well, now I'm baffled.
Click to expand...

Me, too. It's so weird.

Now I tried quite many combinations again. Sorry that one thing I
wrote
in my previous email was wrong. 1GB and 256MB works fine and it
results in 1.25GB.
1GB low density non-ECC + 256MB with-ECC = Will not POST.
Click to expand...

So, this works and it is also 1.25 GB.

Let me put what I've tested:

Bank1 + Bank2 = Total
--------
256MB + 512MB = 768MB
512MB + 256MB = 768MB
1GB + 0 = 1GB
1GB + 256MB = 1.25GB
256MB + 1GB = 1.25GB
1GB + 512MB =1.25GB
512MB + 1GB = 1.25 GB

There is also one more point. I flashed my BIOS just in case
and while looking thought the BIOS option I realized that I can
have this quite memory test in the beginning. There I can see
that the problem is not from Windows at all because at the
beginning BIOS determines the values as I wrote here.
OK, I have a theory. Chip select is broken on one of the
slots, such that only one side of one of the slots
is addressable. This may become more apparent, if you
Click to expand...

Nope, that can't be the case considering the samples I've
written above.

Next thing I will try is buying the same 1 GB module and
trying next to the other 1 GB module. If it works, it would
be good for the performance anyway because the two
slots will have the same memory modules.

Another option would be buying a better quality 1 GB
module, such as Kingston but would it really matter?

-Baris
 
Glad to see you have determined the cause.

Me, too. It's so weird.

Now I tried quite many combinations again. Sorry that one thing I
wrote
in my previous email was wrong. 1GB and 256MB works fine and it
results in 1.25GB.




So, this works and it is also 1.25 GB.

Let me put what I've tested:

Bank1 + Bank2 = Total
--------
256MB + 512MB = 768MB
512MB + 256MB = 768MB
1GB + 0 = 1GB
1GB + 256MB = 1.25GB
256MB + 1GB = 1.25GB
1GB + 512MB =1.25GB
512MB + 1GB = 1.25 GB

There is also one more point. I flashed my BIOS just in case
and while looking thought the BIOS option I realized that I can
have this quite memory test in the beginning. There I can see
that the problem is not from Windows at all because at the
beginning BIOS determines the values as I wrote here.




Nope, that can't be the case considering the samples I've
written above.

Next thing I will try is buying the same 1 GB module and
trying next to the other 1 GB module. If it works, it would
be good for the performance anyway because the two
slots will have the same memory modules.

Another option would be buying a better quality 1 GB
module, such as Kingston but would it really matter?

-Baris
Click to expand...
 
Me, too. It's so weird.

Now I tried quite many combinations again. Sorry that one thing I
wrote
in my previous email was wrong. 1GB and 256MB works fine and it
results in 1.25GB.


So, this works and it is also 1.25 GB.

Let me put what I've tested:

Bank1 + Bank2 = Total
--------
256MB + 512MB = 768MB
512MB + 256MB = 768MB
1GB + 0 = 1GB
1GB + 256MB = 1.25GB
256MB + 1GB = 1.25GB
1GB + 512MB =1.25GB
512MB + 1GB = 1.25 GB

There is also one more point. I flashed my BIOS just in case
and while looking thought the BIOS option I realized that I can
have this quite memory test in the beginning. There I can see
that the problem is not from Windows at all because at the
beginning BIOS determines the values as I wrote here.


Nope, that can't be the case considering the samples I've
written above.

Next thing I will try is buying the same 1 GB module and
trying next to the other 1 GB module. If it works, it would
be good for the performance anyway because the two
slots will have the same memory modules.

Another option would be buying a better quality 1 GB
module, such as Kingston but would it really matter?

-Baris
Click to expand...

It almost looks like the BIOS has capped the total memory.
I wonder if there is a resource conflict somewhere. There
should be plenty of room for AGP aperture, PCI bus mappings
and the like, so there is no excuse.

I found this thread - a user tried 2x1GB in the board, and
got a slowdown in games. Even though the BIOS screen says
the RAM is running at DDR400.

http://forumz.tomshardware.com/hardware/RAM-slowing-loading-ftopict236710.html

I found an MSI tested memory document here, and they have tried
1GB modules in the board. There is no record of them trying
combinations of modules, or two of the same modules.

http://web.archive.org/web/20050825...ucts/mainboard/testreport_pdf/7021/memory.pdf

I notice that a few of the modules are ECC in that document,
so they also seemed to try ones with ECC and ones without.

Would you happen to have a PCI video card ? Say, swap out
the AGP video card, and try a PCI one. Other than that,
I don't understand why the total memory is being capped
at 1.25GB.

Paul
 
I didn't completely read all posts, so you may have looked already. Look in
MB manual to check if there are any jumper settings on the motherboard that
need to be set for memory.
 
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