2Gb Ram fails to boot on Asus A7A266-E

U

uk_techie_2005

I recently purchased two 1Gb 184-pin PC2100 unbuffered DIMMs from
Crucial memory (Part No. CT12864Z265.16TD) to upgrade my Asus A7A266-E
motherboard from 512Mb RAM to the maximum 2Gb Ram (as stated on Pg 22
of MB manual). The manual also mentions it supports 2.5V 1Gb 184-pin
PC2100 unbuffered DIMM.

I have upgraded the BIOS on the motherboard from Rev 1010 to 1012
(latest release version) but I cannot get the PC to boot with both 1Gb
DIMMs in the two available DDR slots (2Gb RAM). Either one of the 1GB
DIMMs works (1GB RAM) but when I place two in the PC fails to boot
beyond the BIOS screen. The PC will also boot up with one of the 1Gb
DIMMSs in one of the slots and one of the original 256Mb DIMMs in the
other slot (1.2Gb RAM).

It completes the memory check, shows the hardware in the machine (Hard
disks, processor, memory) and then hangs. Sometimes it shows ESCD
updated successfully then hangs and sometimes it just hangs after the
BIOS screen.

I have noticed some memory problems on the newsgroups relating to this
motherboard but these either are not applicable or were fixed in later
revisions of the BIOS. I did also notice there is a DDR RAM jumper on
the motherboard to take the voltage from 2.5V to 2.6V, but it states
in the manual this stresses components more and I am reluctant to
increase the voltage as the memory is rated at 2.5V.

If anyone else has had similar issues or knows of a fix for this I
would really appreciate it.

Thanks in advance.
 
B

Ben Pope

I recently purchased two 1Gb 184-pin PC2100 unbuffered DIMMs from
Crucial memory (Part No. CT12864Z265.16TD) to upgrade my Asus A7A266-E
motherboard from 512Mb RAM to the maximum 2Gb Ram (as stated on Pg 22
of MB manual). The manual also mentions it supports 2.5V 1Gb 184-pin
PC2100 unbuffered DIMM.

I have upgraded the BIOS on the motherboard from Rev 1010 to 1012
(latest release version) but I cannot get the PC to boot with both 1Gb
DIMMs in the two available DDR slots (2Gb RAM). Either one of the 1GB
DIMMs works (1GB RAM) but when I place two in the PC fails to boot
beyond the BIOS screen. The PC will also boot up with one of the 1Gb
DIMMSs in one of the slots and one of the original 256Mb DIMMs in the
other slot (1.2Gb RAM).

It completes the memory check, shows the hardware in the machine (Hard
disks, processor, memory) and then hangs. Sometimes it shows ESCD
updated successfully then hangs and sometimes it just hangs after the
BIOS screen.

I have noticed some memory problems on the newsgroups relating to this
motherboard but these either are not applicable or were fixed in later
revisions of the BIOS. I did also notice there is a DDR RAM jumper on
the motherboard to take the voltage from 2.5V to 2.6V, but it states
in the manual this stresses components more and I am reluctant to
increase the voltage as the memory is rated at 2.5V.

If anyone else has had similar issues or knows of a fix for this I
would really appreciate it.

Hmm, it should work. Crucial say it should work, the board says it'll
work, not too many chips on the DIMM... it all looks good.

What are your voltages reading in the BIOS when it does boot (with 2 DIMMs)?

Try 2.6V to test it out... it'll be fine.

Ben
 
P

Paul

I recently purchased two 1Gb 184-pin PC2100 unbuffered DIMMs from
Crucial memory (Part No. CT12864Z265.16TD) to upgrade my Asus A7A266-E
motherboard from 512Mb RAM to the maximum 2Gb Ram (as stated on Pg 22
of MB manual). The manual also mentions it supports 2.5V 1Gb 184-pin
PC2100 unbuffered DIMM.

I have upgraded the BIOS on the motherboard from Rev 1010 to 1012
(latest release version) but I cannot get the PC to boot with both 1Gb
DIMMs in the two available DDR slots (2Gb RAM). Either one of the 1GB
DIMMs works (1GB RAM) but when I place two in the PC fails to boot
beyond the BIOS screen. The PC will also boot up with one of the 1Gb
DIMMSs in one of the slots and one of the original 256Mb DIMMs in the
other slot (1.2Gb RAM).

It completes the memory check, shows the hardware in the machine (Hard
disks, processor, memory) and then hangs. Sometimes it shows ESCD
updated successfully then hangs and sometimes it just hangs after the
BIOS screen.

I have noticed some memory problems on the newsgroups relating to this
motherboard but these either are not applicable or were fixed in later
revisions of the BIOS. I did also notice there is a DDR RAM jumper on
the motherboard to take the voltage from 2.5V to 2.6V, but it states
in the manual this stresses components more and I am reluctant to
increase the voltage as the memory is rated at 2.5V.

If anyone else has had similar issues or knows of a fix for this I
would really appreciate it.

Thanks in advance.

DIMM datasheet:
http://www.micron.com/products/modules/ddrsdram/part.aspx?part=MT16VDDT12864AG-265
Mobo chipset:
http://www.uli.com.tw/eng/products/product_detail.php?pserno=70

It isn't likely that the chipset (or the motherboard design for that
matter), was tested with 1GB sticks. But, at least based on the info
above, it should work.

A simple test, is to drop the CPU FSB to 100MHz, as a quick test.
If the problem is module loading, slowing everything down may
be enough to get it to work. At PC2100, boosting the voltage to the
DIMM should not be required (up to 2.75V is generally safe, unless the
manufacturer states otherwise - the datasheet above states 2.7V).

If you are running Win98, there is a memory limit:
http://groups.google.ca/[email protected]

There is a beta BIOS (1013e001.zip) here:
http://au.asus.com/support/download...0&l3_id=17&m_id=2&f_name=1013e001.zip~zaqwedc

If you still aren't getting anywhere, file a case report, and see if 1GB
modules were ever tested on the board. I've never tried it, but there
are links like this one. Based on the info you provide, you might get a
response. Using the case number generated, if you don't get an answer in
a couple of days, give them a call. The answer will have to come from
the factory.

http://vip.asus.com/eservice/techserv.aspx

HTH,
Paul
 
U

uk_techie_2005

DIMM datasheet:
http://www.micron.com/products/modules/ddrsdram/part.aspx?part=MT16VDDT12864AG-265
Mobo chipset:
http://www.uli.com.tw/eng/products/product_detail.php?pserno=70

It isn't likely that the chipset (or the motherboard design for that
matter), was tested with 1GB sticks. But, at least based on the info
above, it should work.

A simple test, is to drop the CPU FSB to 100MHz, as a quick test.
If the problem is module loading, slowing everything down may
be enough to get it to work. At PC2100, boosting the voltage to the
DIMM should not be required (up to 2.75V is generally safe, unless the
manufacturer states otherwise - the datasheet above states 2.7V).

If you are running Win98, there is a memory limit:
http://groups.google.ca/[email protected]

There is a beta BIOS (1013e001.zip) here:
http://au.asus.com/support/download...0&l3_id=17&m_id=2&f_name=1013e001.zip~zaqwedc

If you still aren't getting anywhere, file a case report, and see if 1GB
modules were ever tested on the board. I've never tried it, but there
are links like this one. Based on the info you provide, you might get a
response. Using the case number generated, if you don't get an answer in
a couple of days, give them a call. The answer will have to come from
the factory.

http://vip.asus.com/eservice/techserv.aspx

HTH,
Paul

All,

Thanks for your replies and useful info. After reading these postings
I tried the following:

1. Changing the jumper on the motherboard from 2.5V (default) to 2.6V.
The PC still didn't boot past the BIOS screen.

2. Tried altering the Latency values in the BIOS but found I couldn't
alter them above the default settings (they would go lower but not
higher):

SDRAM CAS LATENCY 2.5T DDR/3T SDR
SDRAM RAS to CAS LATENCY 3T
SDRAM RAS PRECHARGE TIME 3T
SDRAM CYCLE TIME TO RAS 7T

Also most of these seem to affect SDRAM and not DDR RAM.

I'm reluctant to upgrade the BIOS to a beta version as it is beta
software and they don't list in the BIOS details what fixes it
contains. I don't think it makes a difference as the PC doesn't boot
past the BIOS but I am using windows XP.

Also as suggested here I have opened cases with both ASUS and Crucial
memory to see if I can get an anwser.

Thanks again for everyone's help, it's given me some useful pointers.
If I get a resolution I'll post it here.
 
U

uk_techie_2005

All,

Thanks for your replies and useful info. After reading these postings
I tried the following:

1. Changing the jumper on the motherboard from 2.5V (default) to 2.6V.
The PC still didn't boot past the BIOS screen.

2. Tried altering the Latency values in the BIOS but found I couldn't
alter them above the default settings (they would go lower but not
higher):

SDRAM CAS LATENCY 2.5T DDR/3T SDR
SDRAM RAS to CAS LATENCY 3T
SDRAM RAS PRECHARGE TIME 3T
SDRAM CYCLE TIME TO RAS 7T

Also most of these seem to affect SDRAM and not DDR RAM.

I'm reluctant to upgrade the BIOS to a beta version as it is beta
software and they don't list in the BIOS details what fixes it
contains. I don't think it makes a difference as the PC doesn't boot
past the BIOS but I am using windows XP.

Also as suggested here I have opened cases with both ASUS and Crucial
memory to see if I can get an anwser.

Thanks again for everyone's help, it's given me some useful pointers.
If I get a resolution I'll post it here.


I received a reply from ASUS tech support and Crucial. Crucial
suggested increasing the DDR RAM voltage to 2.7V and lowering the FSB
speed, if this didn't work they suggested contacting ASUS.

The reply I received from ASUS was:

I'm afraid the board cannot handle 2 sticks of that memory, you will
have to find an alternative memory GB module to use.

this raises a couple of questions:

1. If the manual states the board supports 2 x 1Gb RAM of a certain
specification, it should work with any brand of memory as long as it
meets that specification?

2. They don't mention what memory will work! (I emailed them back to
find out what memory will work and await a reply).

If you needed a particular brand of memory to utilise the full 2Gb
shouldn't this be specified in the manual or at least a link to a
website with an approved hardware list (similar to Sun and Microsoft
hardware lists).

Anyone got any ideas or comments?
 
P

Paul

I received a reply from ASUS tech support and Crucial. Crucial
suggested increasing the DDR RAM voltage to 2.7V and lowering the FSB
speed, if this didn't work they suggested contacting ASUS.

The reply I received from ASUS was:

I'm afraid the board cannot handle 2 sticks of that memory, you will
have to find an alternative memory GB module to use.

this raises a couple of questions:

1. If the manual states the board supports 2 x 1Gb RAM of a certain
specification, it should work with any brand of memory as long as it
meets that specification?

2. They don't mention what memory will work! (I emailed them back to
find out what memory will work and await a reply).

If you needed a particular brand of memory to utilise the full 2Gb
shouldn't this be specified in the manual or at least a link to a
website with an approved hardware list (similar to Sun and Microsoft
hardware lists).

Anyone got any ideas or comments?

With 1GB modules, there are different ways of making the
modules. If the modules were designed according to JEDEC
standards, there is a good chance they would use x8 chips.
(That is, the data bus on each memory chip is eight bits
wide. Eight of the x8 chips forms a 64 bit wide array, or
rank of memory. With two of those groups, popularly
referred to as "double sided", we get enough memory to
make the 1GB total. Thus (16) 64megabit x 8 chips makes
a JEDEC approved DIMM.)

Example of a "good" module (from Kingston):
http://www.valueram.com/datasheets/KVR266X64C25_1G.pdf

Proper DIMM modules are likely twice as expensive as
"stacked" DIMMs. There are various ways to make a stacked
DIMM. One way, would be to make a single rank of memory,
using (16) x4 chips. This has the same number of address
loads on the address bus (which is a common reason for
a bus overload), but the (16) x4 chips places twice
the normal load on certain of the control signals. A
"stacked" DIMM just might run, if the memory clock is
dropped a lot. There might even be details about the
refresh method that are different and incompatible.

Stacked construction is fine, when it occurs on a
registered DIMM. But unbuffered DIMMs, like the ones
you are trying to use, really have to live by the
rules, to be expected to work.

Suffice it to say, there is a group of shady vendors
who revel in selling these "stacked" DIMMs. It is my
theory, that they do it, so they can collect the
restocking fee, when the customer insists on returning
the product. Since a stacked DIMM is half the price of
a proper DIMM, many customers are suckered by the price.

To their credit, some of the weasels who list on
Pricewatch, now post a statement either listing which
chipsets they think can drive the stacked DIMMs, or
they flat out say it is stacked or non-standard in some
way.

An example of a good supplier, is Mushkin. Mushkin
sold stacked DIMMs, but each web page contained info
to that effect, so there was no doubt left as to what
you were getting.

I do hope that Asus replies to your query, as I'd like
to see what they have to say about the good and bad
module designs. Asus does provide a QVL (qualified
vendor list) for the use of memory on motherboards,
but because details of their testing methods are not
stated, I have no faith in those lists.

The following is quoted from the Mushkin "DDR Mainboard
Qualification" web pages (I'd give a URL, but they use
inline cookies that cause the URL to be invalid in a
couple of hours):

"Before considering investment of your money in GigaByte
density modules, please read the following:

The load on the clock generator as well as the address and
command bus of the memory controller increases in a linear
fashion with higher memory configurations. Each chip has a
certain input capacitance and if the number of chips is doubled,
the amount of work that has to be done by the controller will
be doubled as well.

Higher load, in turn, will slow down the signal. Therefore,
by definition, higher system memory configurations will have to
run at lower frequencies than low density configurations. High
quality components will be able to partially ameliorate this
problem, however, the tuning of the overall chipset and memory
timing will be the most critical factor for whether the system
will be able to handle e.g. 2 GB of total memory.

Everybody knows about CAS latency but there are other factors
like setup and hold time, Read Latch Delay, Data I/O strobe
delay (DDR only) and drive strength adjustments that need to be
precisely tuned. Because of the competition, every manufacturer
tries to squeeze the maximum performance out of their boards
which is potentially counterproductive for handling high memory
loads.

Try to envision a horse trailer being pulled by a Porsche, how
long will it take until the clutch burns?

Therefore, sometimes, the very fastest and most stable boards
will have the most difficulties with extreme memory
configurations whereas the "workhorse" computer will just put
it away and go on with life. Because of the lack of
predictability, we are carefully testing as many boards as we
can handle to make sure that we can provide the correct
guidelines and recommendations for the GigaByte workspace."

They are referring to their stacked modules in the above, and
by testing which boards work or don't work, are doing a lot more
than your average sleazy seller of stacked DIMMs.

If you got a real bargain on your DIMMs, that is one indicator
you may have got some stacked DIMMs on your hands. But, since
the A7A266 was probably never tested with 1GB modules, when it
was being designed, there is also no way of knowing whether
the BIOS is properly designed to handle them or not. The module
capacities listed in the user manual, are "forward looking
statements", because frequently the highest capacity modules
being mentioned, are simply not available at the time of
introduction. While the motherboard designer will check that
the row/column drive of the Northbridge is appropriate for
what the industry expectation is, for the chips that will be
used on the high density modules, they won't know for sure
until that memory starts shipping.

HTH,
Paul
 

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