A7A266 issue upgrading DDR Ram

  • Thread starter Thread starter y.nabeel
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y.nabeel

Hi there,

I have been using this board for few years with PC133 Ram with no
issue. I just 333 DDR Ram. I removed the SDRAM and installed the single
stick 512 in the DDR slot. the copmuter start so dose the hard drive
but there is no video no beeping. By the way the power light in the
front of the computer keep flashing and I am unable to turn-off the PC,
until I remove the RAM and install the SDRAM again and everything works
fine. I tried to different 512 DDR sticks with no luck. Any advice.
thanks in advance.

Nab
 
Hi there,

I have been using this board for few years with PC133 Ram with no
issue. I just 333 DDR Ram. I removed the SDRAM and installed the single
stick 512 in the DDR slot. the copmuter start so dose the hard drive
but there is no video no beeping. By the way the power light in the
front of the computer keep flashing and I am unable to turn-off the PC,
until I remove the RAM and install the SDRAM again and everything works
fine. I tried to different 512 DDR sticks with no luck. Any advice.
thanks in advance.

Nab
Click to expand...

If DSW switch 5 is set to the "SDRAM only" position, maybe
that is the problem ? I could understand if the switch flipped
between SDRAM and DDR, but it switches between "SDRAM only" and
"Auto detect", which seems kinda silly.

http://support.asus.com/faq/faq_rig...8-E734-A1E1-711A-355777C0742F&SLanguage=en-us

I also noticed on the download page, one of the BIOS releases
mentioned fixing a problem with Samsung DDR memory. They don't
say what the problem was, or what they fixed.

Paul
 
Hi there,

I have been using this board for few years with PC133 Ram with no
issue. I just 333 DDR Ram. I removed the SDRAM and installed the single
stick 512 in the DDR slot. the copmuter start so dose the hard drive
but there is no video no beeping. By the way the power light in the
front of the computer keep flashing and I am unable to turn-off the PC,
until I remove the RAM and install the SDRAM again and everything works
fine. I tried to different 512 DDR sticks with no luck. Any advice.
thanks in advance.
Click to expand...

There is a dipswitch near the AGP port. It's not mentioned in the
manual, but it's supposedly related to the DDR voltage. Try moving the
dipswitch to the other position, and boot, or remove it altogether -
that did the trick for me.

RJT
 
There is a dipswitch near the AGP port. It's not mentioned in the
manual, but it's supposedly related to the DDR voltage. Try moving the
dipswitch to the other position, and boot, or remove it altogether -
that did the trick for me.

RJT
Click to expand...

Interesting. I have a TUA266, which was released at the same
time as the A7A266. Both boards support SDRAM and DDR. The
jumper next to the AGP slot on that board, is called JP25.
It selects between running the DDR slots at 2.5V or 2.6V.
The default is 2.5V, and is the leftmost position. To
try 2.6V, move the jumper to the rightmost position.

I only ever tried to use SDRAM on the TUA266, so never
got to use the DDR slots.

Paul
 
Thanks Paul and RJT you are right as soon as I switched the jumper
setting to Off it accepted the DDR RAM. Now my problem is as I am
working on the PC all of sudden it reboots itself. I had read somewhere
there might an issue with DDR and windows XP and this board. Has anyone
of run into this problem and if so how did you solve it. By the way I
have placed ti 512 sticks of RAM in the unit one of them is Kinston the
other I am not sure. and I have never upgrade the Bios. Thanks for all
your help in advance.

Nab
 
"Nab" said:
Thanks Paul and RJT you are right as soon as I switched the jumper
setting to Off it accepted the DDR RAM. Now my problem is as I am
working on the PC all of sudden it reboots itself. I had read somewhere
there might an issue with DDR and windows XP and this board. Has anyone
of run into this problem and if so how did you solve it. By the way I
have placed ti 512 sticks of RAM in the unit one of them is Kinston the
other I am not sure. and I have never upgrade the Bios. Thanks for all
your help in advance.

Nab
Click to expand...

I would get a copy of CPUZ from www.cpuid.com and check
the system frequencies and memory timings.

You have the option of Jumper mode or JumperFree mode.
You may end up trying both modes, to try and get stability.

I notice the DSW offers a number of options for CPU clock
and memory clock. But JumperFree offers more options, as
the BIOS can program the clockgen chip to more different
possible combinations. If your CPU is being fed a 133Mhz
clock, you might try running the memory at 100MHz, to
see if that improves stability. You also have the option
of adjusting memory timings.

(Note: the values that are multiples of 33Mhz are the best,
because they will result in the PCI bus clock being 33MHz
also. Older boards like the A7A266 use dividers to generate
the PCI clock, and if you use say 120MHz, a divider of 3
might be used to make the PCI clock, and anything over 37.5MHz
for PCI will likely cause a peripheral, like a disk drive,
to fail to operate correctly. A value of 100 gets a divider
of 3, a value of 133 gets a divider of 4, both of which give
a PCI clock of 33MHz.)

In any case, I would start with CPUZ and see what values
are being used. Perhaps you could post more details about
your CPU, the brand of memory and what timings it is supposed
to use, and whatever things you see in CPUZ.

I hope the A7A266 has given you some stable operation - I
spent three weeks fiddling with my TUA266 and could not
tame the AGP slot. The TUA266 is the only Asus motherboard
that I couldn't fix :-(

Paul
 
"Nab" said:
Thanks Paul and RJT you are right as soon as I switched the jumper
setting to Off it accepted the DDR RAM. Now my problem is as I am
working on the PC all of sudden it reboots itself. I had read somewhere
there might an issue with DDR and windows XP and this board. Has anyone
of run into this problem and if so how did you solve it. By the way I
have placed ti 512 sticks of RAM in the unit one of them is Kinston the
other I am not sure. and I have never upgrade the Bios. Thanks for all
your help in advance.

Nab
Click to expand...

After reading a number of postings in some of the private forums,
I get the impression that a memory stick with a higher performance
rating is needed to get stability. For example, a PC3200 (DDR400)
memory would be backward compatible with PC2100, as long as the BIOS
doesn't have some weird problem with it. Back in the days when the
A7A266 was introduced, people were using some kind of Mushkin
overclocker memory, to get the board to work. I would _think_
that a stick of PC3200 memory should have the same beneficial
effect. If it is CAS2 or CAS2.5, so much the better.

Other comments were, that the board is happier with SDRAM.
I presume that comment is from people who tried ordinary DDR
and got results like you.

Paul
 
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