Motherboard will not post with 4GB

Four and a half years ago, I build a system with an Asus P5KPL-CM as a
motherboard, with 2 x 2GB PC2-6400 RAM modules. It has run well for
that time, but now locks up on POST. (The splash screen does not even
finish painting.)

If I pull either one of the memory modules, from either one of the
slots, the system will boot.

If I put in 2 x 1GB PC2-6400 RAM, the system will boot.

If I put in a diffent 2 x 2GB PC2-6400 RAM modules, the system will not
boot. Either module in either slot allows the system to boot.

The BIOS has been updated to the current version, but it has had no
effect on this odd behavior.

Any speculations as to what might be going on?

On 03/03/2014 05:12 PM, Grinder wrote:
Four and a half years ago, I build a system with an Asus P5KPL-CM as a
motherboard, with 2 x 2GB PC2-6400 RAM modules. It has run well for
that time, but now locks up on POST. (The splash screen does not even
finish painting.)

If I pull either one of the memory modules, from either one of the
slots, the system will boot.

If I put in 2 x 1GB PC2-6400 RAM, the system will boot.

If I put in a diffent 2 x 2GB PC2-6400 RAM modules, the system will not
boot. Either module in either slot allows the system to boot.

The BIOS has been updated to the current version, but it has had no
effect on this odd behavior.

Any speculations as to what might be going on?




No idea. Did you try setting the BIOS to default?

Grinder wrote:
Four and a half years ago, I build a system with an Asus P5KPL-CM as a
motherboard, with 2 x 2GB PC2-6400 RAM modules. It has run well for
that time, but now locks up on POST. (The splash screen does not even
finish painting.)

If I pull either one of the memory modules, from either one of the
slots, the system will boot.

If I put in 2 x 1GB PC2-6400 RAM, the system will boot.

If I put in a diffent 2 x 2GB PC2-6400 RAM modules, the system will not
boot. Either module in either slot allows the system to boot.

The BIOS has been updated to the current version, but it has had no
effect on this odd behavior.

Any speculations as to what might be going on?


A failure at 2x2GB here as well.

http://vip.asus.com/forum/view.aspx?...Language=en-us

I checked the G31 datasheet, and it does have a 36 bit FSB interface.
Which implies it supports memory hoisting. That makes it a tiny
bit less likely, that this is a 4GB hardware barrier issue. It has two
channels, supports one DIMM per channel, accepts 2GB DIMMs (16 chips per DIMM).
For a total of 4GB. Any memory not fitting in the address space, should
be hoisted out of the way, above 4GB. And be ignored by a 32 bit OS.

If the G31 graphics are turned off, you might turn them on. Even
if not using them. Perhaps if it uses up a bit of RAM for the
G31, that'll be enough to "correct" the memory map.

The forum above, there seem to be a lot of issues with the BIOS design.
There was at least one quite different motherboard in the past, where
there was something wrong with the memory map, and "USB overcurrent" would
flash up on the OS screen, due to some overlap between some
motherboard resource and system memory. Try playing with things that
consume RAM (such as G31 GPU setting) and see if that helps.

Another possible issue, is 1GB DIMMs versus 2GB DIMMs. When
2GB DIMMS came out, many BIOS lacked "tuning" for them. Insert
a 2GB DIMM, and it would throw errors. But, you've tested with
1x2GB and passed, so it's probably not an optimization problem.
I have a motherboard here, where 2GB DIMMs are still unstable,
while 1GB DIMMs are "rock solid". You can Prime95 forever with
the 1GB DIMMs, and nothing bad happens.

So my wild guess would be:

1) Immature BIOS (designed by the B-team)
2) Memory map problem. Toggle any control that you think
might impact the BIOS constructed memory map.
3) I was considering a suggestion of changing PNP OS setting
from No to Yes, but I don't really think that would do
anything.

HTH,
Paul

On 3/3/2014 7:04 PM, philo wrote:
On 03/03/2014 05:12 PM, Grinder wrote:
Four and a half years ago, I build a system with an Asus P5KPL-CM as a
motherboard, with 2 x 2GB PC2-6400 RAM modules. It has run well for
that time, but now locks up on POST. (The splash screen does not even
finish painting.)

If I pull either one of the memory modules, from either one of the
slots, the system will boot.

If I put in 2 x 1GB PC2-6400 RAM, the system will boot.

If I put in a diffent 2 x 2GB PC2-6400 RAM modules, the system will not
boot. Either module in either slot allows the system to boot.

The BIOS has been updated to the current version, but it has had no
effect on this odd behavior.

Any speculations as to what might be going on?




No idea. Did you try setting the BIOS to default?

Yes--both manually, and as an option when I flashed the BIOS.

On 3/3/2014 8:27 PM, Paul wrote:
Grinder wrote:
Four and a half years ago, I build a system with an Asus P5KPL-CM as a
motherboard, with 2 x 2GB PC2-6400 RAM modules. It has run well for
that time, but now locks up on POST. (The splash screen does not even
finish painting.)

If I pull either one of the memory modules, from either one of the
slots, the system will boot.

If I put in 2 x 1GB PC2-6400 RAM, the system will boot.

If I put in a diffent 2 x 2GB PC2-6400 RAM modules, the system will
not boot. Either module in either slot allows the system to boot.

The BIOS has been updated to the current version, but it has had no
effect on this odd behavior.

Any speculations as to what might be going on?


A failure at 2x2GB here as well.

http://vip.asus.com/forum/view.aspx?...Language=en-us


I checked the G31 datasheet, and it does have a 36 bit FSB interface.
Which implies it supports memory hoisting. That makes it a tiny
bit less likely, that this is a 4GB hardware barrier issue. It has two
channels, supports one DIMM per channel, accepts 2GB DIMMs (16 chips per
DIMM).
For a total of 4GB. Any memory not fitting in the address space, should
be hoisted out of the way, above 4GB. And be ignored by a 32 bit OS.

If the G31 graphics are turned off, you might turn them on. Even
if not using them. Perhaps if it uses up a bit of RAM for the
G31, that'll be enough to "correct" the memory map.

The onboard video is in use.

The forum above, there seem to be a lot of issues with the BIOS design.
There was at least one quite different motherboard in the past, where
there was something wrong with the memory map, and "USB overcurrent" would
flash up on the OS screen, due to some overlap between some
motherboard resource and system memory. Try playing with things that
consume RAM (such as G31 GPU setting) and see if that helps.

Another possible issue, is 1GB DIMMs versus 2GB DIMMs. When
2GB DIMMS came out, many BIOS lacked "tuning" for them. Insert
a 2GB DIMM, and it would throw errors. But, you've tested with
1x2GB and passed, so it's probably not an optimization problem.
I have a motherboard here, where 2GB DIMMs are still unstable,
while 1GB DIMMs are "rock solid". You can Prime95 forever with
the 1GB DIMMs, and nothing bad happens.

So my wild guess would be:

1) Immature BIOS (designed by the B-team)
2) Memory map problem. Toggle any control that you think
might impact the BIOS constructed memory map.
3) I was considering a suggestion of changing PNP OS setting
from No to Yes, but I don't really think that would do
anything.

Thanks, Paul--will tinker and let you know if anything comes of it.