P5B=VM Memory Use

I just put a system together using an ASUS P5B-VM with an Intel Core 2
Duo 6400 CPU. I wanted to use 2 GB memory (4 sticks of 512MB Kingston
DS) as listed in the manual as qualified memory for this MB. The
system runs normal and stable with 1 GB mem, but with 2 GB, all four
mem slots filled, it's unstable as hell and fails memtest big time.
Using the settings listed on page 2-19 of the manual in all various
combinations makes no difference. I left the mem & CPU voltages in
auto as I really don't have a good feel for the impact they would have
on the system if I imput something wrong.

I have Win XP installed and it runs fine with 1 GB memory. I installed
a ATI X 1950 Pro express 16 card in it but it ran fine with the
onboard video also.

Any one running this same MB with all mem slots filled, or have any
suggestion on why the board wont handle 2 GB mem>

Dewayne Thomas wrote:
> I just put a system together using an ASUS P5B-VM with an Intel Core 2
> Duo 6400 CPU. I wanted to use 2 GB memory (4 sticks of 512MB Kingston
> DS) as listed in the manual as qualified memory for this MB. The
> system runs normal and stable with 1 GB mem, but with 2 GB, all four
> mem slots filled, it's unstable as hell and fails memtest big time.
> Using the settings listed on page 2-19 of the manual in all various
> combinations makes no difference. I left the mem & CPU voltages in
> auto as I really don't have a good feel for the impact they would have
> on the system if I imput something wrong.
>
> I have Win XP installed and it runs fine with 1 GB memory. I installed
> a ATI X 1950 Pro express 16 card in it but it ran fine with the
> onboard video also.
>
> Any one running this same MB with all mem slots filled, or have any
> suggestion on why the board wont handle 2 GB mem>

Anytime you add memory, that additional memory draws current, making the
total load of the memory voltage higher. The fix is simple: go into the
BIOS and increase the voltage for the memory. Increase by one step,
test the system and if it is not stable, increase the voltage again.
Repeat till you have stability, although you shouldn't have to go too
far to fix the problem.

On Fri, 8 Jun 2007 14:08:23 -0400, "Robv" <>
wrote:

>Dewayne Thomas wrote:
>> I just put a system together using an ASUS P5B-VM with an Intel Core 2
>> Duo 6400 CPU. I wanted to use 2 GB memory (4 sticks of 512MB Kingston
>> DS) as listed in the manual as qualified memory for this MB. The
>> system runs normal and stable with 1 GB mem, but with 2 GB, all four
>> mem slots filled, it's unstable as hell and fails memtest big time.
>> Using the settings listed on page 2-19 of the manual in all various
>> combinations makes no difference. I left the mem & CPU voltages in
>> auto as I really don't have a good feel for the impact they would have
>> on the system if I imput something wrong.
>>
>> I have Win XP installed and it runs fine with 1 GB memory. I installed
>> a ATI X 1950 Pro express 16 card in it but it ran fine with the
>> onboard video also.
>>
>> Any one running this same MB with all mem slots filled, or have any
>> suggestion on why the board wont handle 2 GB mem>
>
>Anytime you add memory, that additional memory draws current, making the
>total load of the memory voltage higher. The fix is simple: go into the
>BIOS and increase the voltage for the memory. Increase by one step,
>test the system and if it is not stable, increase the voltage again.
>Repeat till you have stability, although you shouldn't have to go too
>far to fix the problem.
>

The selections for the mem voltage start at 1.8V up to 1.95V in
increments of .05. I went up to 1.95 and memtest still failed. I was
hestant to go beyond that with out some knowledgable suggestions.

Thank, Robv, for the info though. I don't know if you can keypad in a
setting, but if you can what would be the max voltage I could use
without frying something?

Dewayne Thomas wrote:

[snip]

>> Anytime you add memory, that additional memory draws current, making
>> the total load of the memory voltage higher. The fix is simple: go
>> into the BIOS and increase the voltage for the memory. Increase by
>> one step, test the system and if it is not stable, increase the
>> voltage again. Repeat till you have stability, although you
>> shouldn't have to go too far to fix the problem.
>>
>
> The selections for the mem voltage start at 1.8V up to 1.95V in
> increments of .05. I went up to 1.95 and memtest still failed. I was
> hestant to go beyond that with out some knowledgable suggestions.
>
> Thank, Robv, for the info though. I don't know if you can keypad in a
> setting, but if you can what would be the max voltage I could use
> without frying something?

What is the minimum voltage required for that memory? If you're not
sure, give me the exact model number, etc. of the memory you have. I
know it's 512 MB sticks and it's Kingston, but the exact model/part
number will help to find the voltage requirements.

Dewayne Thomas wrote:
> I just put a system together using an ASUS P5B-VM with an Intel Core 2
> Duo 6400 CPU. I wanted to use 2 GB memory (4 sticks of 512MB Kingston
> DS) as listed in the manual as qualified memory for this MB. The
> system runs normal and stable with 1 GB mem, but with 2 GB, all four
> mem slots filled, it's unstable as hell and fails memtest big time.
> Using the settings listed on page 2-19 of the manual in all various
> combinations makes no difference. I left the mem & CPU voltages in
> auto as I really don't have a good feel for the impact they would have
> on the system if I imput something wrong.
>
> I have Win XP installed and it runs fine with 1 GB memory. I installed
> a ATI X 1950 Pro express 16 card in it but it ran fine with the
> onboard video also.
>
> Any one running this same MB with all mem slots filled, or have any
> suggestion on why the board wont handle 2 GB mem>
>

Perhaps you could use CPUZ, to verify that the settings in the BIOS
are being used.

http://www.cpuid.com/cpuz.php
http://www.cpuid.com/download/cpu-z-140.zip

Compare the numbers, to the ratings for your RAM.

The "registers dump" function, will make a text file for you, if you
ever need to copy and paste any of the info. The raw SPD EEPROM info
appears just below "Dump Module #1" etc.

Paul

Paul wrote:

[snip]

> Perhaps you could use CPUZ, to verify that the settings in the BIOS
> are being used.
>
> http://www.cpuid.com/cpuz.php
> http://www.cpuid.com/download/cpu-z-140.zip
>
> Compare the numbers, to the ratings for your RAM.
>
> The "registers dump" function, will make a text file for you, if you
> ever need to copy and paste any of the info. The raw SPD EEPROM info
> appears just below "Dump Module #1" etc.
>
> Paul

Excellent suggestion.

On Fri, 8 Jun 2007 16:41:41 -0400, "Robv" <>
wrote:

>Dewayne Thomas wrote:
>
>[snip]
>
>>> Anytime you add memory, that additional memory draws current, making
>>> the total load of the memory voltage higher. The fix is simple: go
>>> into the BIOS and increase the voltage for the memory. Increase by
>>> one step, test the system and if it is not stable, increase the
>>> voltage again. Repeat till you have stability, although you
>>> shouldn't have to go too far to fix the problem.
>>>
>>
>> The selections for the mem voltage start at 1.8V up to 1.95V in
>> increments of .05. I went up to 1.95 and memtest still failed. I was
>> hestant to go beyond that with out some knowledgable suggestions.
>>
>> Thank, Robv, for the info though. I don't know if you can keypad in a
>> setting, but if you can what would be the max voltage I could use
>> without frying something?
>
>What is the minimum voltage required for that memory? If you're not
>sure, give me the exact model number, etc. of the memory you have. I
>know it's 512 MB sticks and it's Kingston, but the exact model/part
>number will help to find the voltage requirements.
>
The part # is KVR800D2N5K2/1G , Chip # is K4T510830C.The memory Module
Spec list the mem voltage @ +1.8 (+/- .1V) . It also list the power
as 1.872 W (operating per module), which I presume is the min PS
output fed to the mem slot. I have a new Thermaltake TR-2-500W PS,
which should supply the V needed. I'll be running Vista Premium on
this system so would like to have the 2 GB mem if I can get it on
this board.

Dewayne Thomas wrote:
> On Fri, 8 Jun 2007 16:41:41 -0400, "Robv" <>
> wrote:
>
>> Dewayne Thomas wrote:
>>
>> [snip]
>>
>>>> Anytime you add memory, that additional memory draws current,
>>>> making the total load of the memory voltage higher. The fix is
>>>> simple: go into the BIOS and increase the voltage for the memory.
>>>> Increase by one step, test the system and if it is not stable,
>>>> increase the voltage again. Repeat till you have stability,
>>>> although you shouldn't have to go too far to fix the problem.
>>>>
>>>
>>> The selections for the mem voltage start at 1.8V up to 1.95V in
>>> increments of .05. I went up to 1.95 and memtest still failed. I was
>>> hestant to go beyond that with out some knowledgable suggestions.
>>>
>>> Thank, Robv, for the info though. I don't know if you can keypad in
>>> a setting, but if you can what would be the max voltage I could use
>>> without frying something?
>>
>> What is the minimum voltage required for that memory? If you're not
>> sure, give me the exact model number, etc. of the memory you have. I
>> know it's 512 MB sticks and it's Kingston, but the exact model/part
>> number will help to find the voltage requirements.
>>
> The part # is KVR800D2N5K2/1G , Chip # is K4T510830C.The memory Module
> Spec list the mem voltage @ +1.8 (+/- .1V) . It also list the power
> as 1.872 W (operating per module), which I presume is the min PS
> output fed to the mem slot. I have a new Thermaltake TR-2-500W PS,
> which should supply the V needed. I'll be running Vista Premium on
> this system so would like to have the 2 GB mem if I can get it on
> this board.

Yes, found it. It's been my experience that when you add modules, you
have to raise the memory voltage. I never used Kingston, but the memory
I have now is Corsair, spec voltage is 1.9v. Ran memtest86+ with no
problems with one stick plugged in. When I installed the second stick,
a few random memory errors showed up. I raised the memory voltage to
1.95, then to 2.0, then to 2.05v before the system ran fine, with
memtest86+ and Prime95 with the system running.

I've used OCZ and Crucial memory in other systems and had the same
experience. I was curious about this and called Corsair, whereupon the
support person explained that sometimes the voltage shown in the BIOS is
not the actual voltage due to loading (extra modules) and/or the
hardware reporting the incorrect voltage. It was a canned answer, as I
could hear him reading it. However, he said nothing about the max
voltage to try, and was nonplussed about raising the voltage even more
than 2.0V.

If spec is 1.8V and 1.95 still isn't stable, I would go to 2.0V and no
higher than 2.1V. If you are uncomfortable doing that, you could return
the modules you have for another pair and you may get modules that work
with less voltage.

Paul may have different advice for you. My advice is above, gained
through my experiences, but getting more diverse advice always helps.
:-)

On Fri, 8 Jun 2007 17:16:43 -0400, "RobV" <>
wrote:

>Paul wrote:
>
>[snip]
>
>> Perhaps you could use CPUZ, to verify that the settings in the BIOS
>> are being used.
>>
>> http://www.cpuid.com/cpuz.php
>> http://www.cpuid.com/download/cpu-z-140.zip
>>
>> Compare the numbers, to the ratings for your RAM.
>>
>> The "registers dump" function, will make a text file for you, if you
>> ever need to copy and paste any of the info. The raw SPD EEPROM info
>> appears just below "Dump Module #1" etc.
>>
>> Paul
>
>Excellent suggestion.
>
Thanks, guys, I'll let the info I've gathered today cook awhile and do
some more investigating with a register dump. Last resort I can jack
the mem voltage up to where something smokes, then back off alittle.
Just kidding.

Dewayne

Dewayne Thomas wrote:
> On Fri, 8 Jun 2007 17:16:43 -0400, "RobV" <>
> wrote:
>
>> Paul wrote:
>>
>> [snip]
>>
>>> Perhaps you could use CPUZ, to verify that the settings in the BIOS
>>> are being used.
>>>
>>> http://www.cpuid.com/cpuz.php
>>> http://www.cpuid.com/download/cpu-z-140.zip
>>>
>>> Compare the numbers, to the ratings for your RAM.
>>>
>>> The "registers dump" function, will make a text file for you, if you
>>> ever need to copy and paste any of the info. The raw SPD EEPROM info
>>> appears just below "Dump Module #1" etc.
>>>
>>> Paul
>>
>> Excellent suggestion.
>>
> Thanks, guys, I'll let the info I've gathered today cook awhile and do
> some more investigating with a register dump. Last resort I can jack
> the mem voltage up to where something smokes, then back off alittle.
> Just kidding.
>
> Dewayne

You're welcome, Dewayne.