BIOS setting "Memory over voltage" shows value in red

In the BIOS Setup 'Ai Tweaker' menu of my Asus P5QL/EPU motherboard I
just happened to notice that the BIOS setting "Memory over voltage" is
shown as "2.10000" in *red*.

I find the red colour scary. Why red?

Would I lose anything by changing the setting to 'Auto'?
(What are the implications of doing so?)

Or perhaps reduce by increments until it is no longer red?

N.B. I have never gone in for 'overclocking'. I just happened to
notice the red when scrolling through the Seup menus.

There is 4GB of Corsair Dominator dual-DDR2 1066MHz RAM.

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"Maurice Batey" wrote in message
news
In the BIOS Setup 'Ai Tweaker' menu of my Asus P5QL/EPU motherboard I
just happened to notice that the BIOS setting "Memory over voltage" is
shown as "2.10000" in *red*.

I find the red colour scary. Why red?

Would I lose anything by changing the setting to 'Auto'?
(What are the implications of doing so?)

Or perhaps reduce by increments until it is no longer red?

N.B. I have never gone in for 'overclocking'. I just happened to
notice the red when scrolling through the Seup menus.

There is 4GB of Corsair Dominator dual-DDR2 1066MHz RAM.

--
/\/\aurice
(Retired in Surrey, UK) Registered Linux User #487649
(Replace "nomail.afraid" by "bcs" to reply by email)


It's telling you that you've exceeded the "normal" voltage by some arbitrary
amount. You might try reducing the voltage to, say, 2.05 and see if your PC
is still stable. You set it to 2.10 for some reason, correct? Was the PC
unstable when the BIOS setting was "Auto"?

More voltage means more heat and more stress on the component in question.
Thus, shorter component life. As a practical matter, the "shorter life" will
still probably exceed the useful (until replacement due to obsolescence) by
a lot, so why worry?

It's far more important that your PC run stable and not lose valuable data,
right?

If the red bothers you that much and/or you have heat issues, reduce the
voltage a bit at a time, then run thorough stability tests (Memtest, etc.)
until you're back in the "normal" range and still *stable*. Remember that
the BIOS setting for "red" is generic and your memory's recommended voltage
range may well be different, I.e. the memory spec may say 2.1 is OK.

On Wed, 03 Mar 2010 11:50:11 -0600, PvdG42 wrote:

You might try reducing the voltage to, say, 2.05 and see if your PC
is still stable.

So reducing the voltage may cause some malfunction?

You set it to 2.10 for some reason, correct?

I didn't touch the setting. It's how it was from new.

Was the PC unstable when the BIOS setting was "Auto"?

Haven't tried 'Auto' - because I don't know what 'Auto' implies!
The system has been behaving perfectly. It's the figure being in
*red* that scared me!

It's far more important that your PC run stable and not lose
valuable data, right?

Right!

If the red bothers you that much and/or you have heat issues, reduce
the voltage a bit at a time, then run thorough stability tests
(Memtest, etc.)
until you're back in the "normal" range and still *stable*.

Not familar with 'stability tests', and don't know what 'normal'
range' is.

Remember that the BIOS setting for "red" is generic and your
memory's recommended voltage range may well be different, I.e. the
memory spec may say 2.1 is OK.

Don't understand 'setting for "red" is generic'.

How does one find what the memory's recommended voltage range is?

The BIOS manual says:

"Memory Over Voltage (Default: Auto)
Allows you to set the memory over voltage."
The value ranges from 1.85000V to 2.24375V with a 0.00625V
interval. Configuration options: [Auto]"

So is 'Auto' a safer option than arbitarily reducing the voltage
figure? How does 'Auto' work here?

Sorry to be so dumb here, but it's an area of PC's that I have never
dabbled in.

Many thanks for responding; much appeciated...

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(Replace "nomail.afraid" by "bcs" to reply by email)

the DDR2 Dominators run at 2.1 Voltage
you need to adjust a setting on your mobo for the BIOS to accept that voltage
without thinking it is overvolted(?)
The normal voltage for that board is 1.7v
See this website
http://www.overclockersclub.com/revi.../images/21.htm

your manual should tell you where that jumper is located
there usually is a diagram that points out the switches

peter

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"Maurice Batey" wrote in message
news
On Wed, 03 Mar 2010 11:50:11 -0600, PvdG42 wrote:

You might try reducing the voltage to, say, 2.05 and see if your PC
is still stable.

So reducing the voltage may cause some malfunction?

You set it to 2.10 for some reason, correct?

I didn't touch the setting. It's how it was from new.

Was the PC unstable when the BIOS setting was "Auto"?

Haven't tried 'Auto' - because I don't know what 'Auto' implies!
The system has been behaving perfectly. It's the figure being in
*red* that scared me!

It's far more important that your PC run stable and not lose
valuable data, right?

Right!

If the red bothers you that much and/or you have heat issues, reduce
the voltage a bit at a time, then run thorough stability tests
(Memtest, etc.)
until you're back in the "normal" range and still *stable*.

Not familar with 'stability tests', and don't know what 'normal'
range' is.

Remember that the BIOS setting for "red" is generic and your
memory's recommended voltage range may well be different, I.e. the
memory spec may say 2.1 is OK.

Don't understand 'setting for "red" is generic'.

How does one find what the memory's recommended voltage range is?

The BIOS manual says:

"Memory Over Voltage (Default: Auto)
Allows you to set the memory over voltage."
The value ranges from 1.85000V to 2.24375V with a 0.00625V
interval. Configuration options: [Auto]"

So is 'Auto' a safer option than arbitarily reducing the voltage
figure? How does 'Auto' work here?

Sorry to be so dumb here, but it's an area of PC's that I have never
dabbled in.

Many thanks for responding; much appeciated...

--
/\/\aurice
(Replace "nomail.afraid" by "bcs" to reply by email)

On Wed, 03 Mar 2010 12:44:19 -0700, peter wrote:

you need to adjust a setting on your mobo for the BIOS to accept that voltage
without thinking it is overvolted(?)
The normal voltage for that board is 1.7v
See this website
http://www.overclockersclub.com/revi.../images/21.htm

your manual should tell you where that jumper is located
there usually is a diagram that points out the switches

The PSQL/EPU manual says - of 1066MHx DDR2 RAM:

"If you install a DDR2-1066 memory module whose ?? is
DDR2-800, ensure you set the 'DRAM Frequency' item in the BIOS to
"[DDR2-1066MHz]".

I have checked that and it already has that setting.

I cannot find any reference to "OV_CPU" in the BIOS manual.

Are you saying there is some jumper that has to by physically modified
on the motherboard?

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On Wed, 03 Mar 2010 21:00:45 +0000, Maurice Batey wrote:

The PSQL/EPU manual says - of 1066MHx DDR2 RAM:
...

It also says - for Memory Over Voltage:

"Min = 1.85V Max = 2.24375V"

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Maurice Batey wrote:
On Wed, 03 Mar 2010 21:00:45 +0000, Maurice Batey wrote:

The PSQL/EPU manual says - of 1066MHx DDR2 RAM:
...

It also says - for Memory Over Voltage:

"Min = 1.85V Max = 2.24375V"


The nominal voltage for DDR2 memory is 1.8V. The JEDEC spec
has a tolerance on the nominal voltage, of perhaps +/- 0.1 volts.
(Just going by what I see in a Kingston data sheet.)
That tolerance is intended to cover the accuracy of a voltage
regulator used to feed the DIMM. The regulator puts out 1.8V,
and is allowed to be off by as much as 0.1V.

Enthusiast RAM sometimes requires extra voltage, to meet
timing and frequency specifications. You can take
memory chips that aren't intended to run at that speed,
feed them extra voltage, and get more performance from them.
The Corsair memory could be a product like that. In the
table here, I can see the specs for some Dominator brand
memories.

http://www.corsair.com/products/dominator/default.aspx

****
TWIN2X4096-8500C5D

Speed Rating Tested Speed Size Tested Latency Tested Voltage Performance Profile
PC2-8500 1066Mhz 4GB Kit 5-5-5-15 2.1 EPP
(2 x 2GB)

SPD Speed SPD Latency Package Fan Included
800Mhz 5-5-5-18 240pin DIMM No
****

The term "EPP" means that the SPD chip on the DIMM, contains
additional information about setting up the DIMM. The normal
JEDEC SPD table doesn't contain a field for "overvolting". The
EPP profile does. You can get a copy of the EPP specification
by clicking a link here (archived copy of spec). This spec
covers DDR2.

http://web.archive.org/*/www.corsair...cation_v01.pdf

On page 13, I see this. If you use a copy of CPUZ from cpuid.com,
you may be able to view the EPP profile information. If CPUZ shows
a voltage coming from the SPD table, that is what the BIOS could be
reading.

Table 9. Voltage Level Field
Voltage Level Example Hex Values
1.8V 00h
1.9V 04h
2.0V 08h
2.1V 0Ch
2.2V 10h
2.3V 14h
2.4V 18h
2.5V 1Ch

The purpose of recording 2.1V in the EPP, is to ensure the memory
meets 5-5-5-15 at DDR2-1066. As a user, when you start the motherboard
for the first time, the memory setting might be Auto. If the BIOS
supports EPP profile reading, it will immediately set the voltage
to 2.1V, as specified in the table. This allows the motherboard
to run the RAM at the manufacturer specifications immediately.

A user is allowed to adjust the settings of their enthusiast memory
manually, via the BIOS menu. A smart thing to do, is to gradually
reduce the Vdimm setting, one voltage step at a time, and test
for stability after doing so. If you encounter memory errors in
your testing, then bump the voltage up one notch.

If you misadjusted the memory so badly, that the motherboard could
no longer POST, either the motherboard auto-clearing function or
using the "Clear CMOS" jumper would restore control of the motherboard.
Always unplug the computer if using the "Clear CMOS" jumper, for
safety.

Tools for testing, include memtest86+ from memtest.org, and the
usage of Prime95 (mersenne.org/freesoft) stress test while in Windows
(or Linux). No errors are acceptable in either testing situation.
For memtest, I use two passes as "enough testing". For Prime95,
I accept 4 hours of error free stress testing as enough. After that,
I use the computer, until there are signs that the settings are still
not right. (For example, some 3D games will misbehave, when there are
memory errors.)

Back in the days when ECC memory was more popular, you could rely
on the memory subsystem to detect marginal memory behavior (the
odd error). But without ECC on most desktop memory, you can run
stress tests, but when actually using the system, you're largely
blind as to when memory errors are happening.

I don't see any mention of EPP profile support in the description here
of the BIOS, but there must be support, for the motherboard to have
applied 2.1V as seen in the EPP for that RAM. If you enter the
BIOS and use manual settings for the memory, you should be able
to adjust that (and test after each adjustment). Don't boot Windows
right away, after making a change, as you can actually corrupt
your Windows installation if bad memory is present on your system.
(Writing back a corrupted registry...)

http://dlcdnet.asus.com/pub/ASUS/mb/...EPU-manual.zip

So the memory you bought is rated for 2.1V operation. JEDEC standard
voltage for DDR2 is 1.8V. You can drop the voltage, until you get
to the point that you're detecting errors while doing the various
memory tests. Corsair apparently feels the memory will survive
just fine on 2.1V.

If you're curious about what kind of voltage a DDR2 memory chip can take,
take a look at PDF page 23 here. This Micron chip can take 2.3 volts
as the voltage level before there could be long term damage. So
2.1 volts is still a bit less than that value.

http://download.micron.com/pdf/datas...r2/1GbDDR2.pdf

The Asus coloring scheme, is intended to show you the rough operating
range being used. The "red" is to alert you to the fact that
the JEDEC nominal value is not being used. You then rely on
your other documentation, as to what to do.

HTH,
Paul

On Wed, 03 Mar 2010 18:21:08 -0500, Paul wrote:

I don't see any mention of EPP profile support in the description here
of the BIOS, but there must be support, for the motherboard to have
applied 2.1V as seen in the EPP for that RAM.

No - I have the P5QL/EPU manual PDF file, and could not find any
reference to EPP. but it's interesting to note you think there must
be support in there.
The supplier of the PC have said they do not change any of the
BIOS settings, so the only way the 'memory over voltage' setting
could have changed to 2.1V (and the DRAM Frequency setting to
"DDR"-1066MHz?) must be as you conjecture.

The Asus coloring scheme, is intended to show you the rough
operating range being used. The "red" is to alert you to the fact
that the JEDEC nominal value is not being used.

If that's all that it's trying to say, then I shall leave things as
they are - assuming the setting of 2.1V is not a hazard of any kind.

Corsair apparently feels the memory will survive just fine on
2.1V.

Here are some postings on subject I found on the 'net:

(http://www.tomshardware.co.uk/forum/...66mhz-enabled-
system-unstable)

"The cause of my issue was the BIOS and voltage of RAM. When my
RAM was running @1066MHz the system became unstable and
crash happened. I contacted MSI technical support for the
issue and I updated the BIOS two times and increased RAM
voltage from 2.0V to 2.1V ... After BIOS upgrade and increasing
of voltage I not facing any crashes, hangs or BSoD for some
days.....
I think the main reason of my problem was BIOS compatibity of
1066MHz DDR2 and voltage."

(http://www.tomshardware.co.uk/forum/...voltage-higher)

In my PC i have 2 sticks of DDR2 1066MHz Corsair Dominator
5-5-5-15-2T.
Now this profile can only be achieved by manually setting the
DDR2 voltage to 2.1V in the BIOS and it will automatically
overclock the rest, which is cool, and fully in line with
Corsair's recommendations for these sticks.

Everything works fine, but PC Probe II tells me that the DDR2
Voltage is 2.14V. I know that seems menial, but the .04V means
the difference between a blown DRAM chip and a healthy one and
since i have just RMA'd 2 faulty sticks clocked at the same
settings as above (same make of sticks and everything) I am
worried that maybe my voltage controllers (or whatever these
things are called) are faulty? Or is it PC Probe overestimating
such values?
I'm a tad worried because i do not want to blow these
sticks too!"

(Reply)
"Try another voltage reporter, eg CPUID Hardware Monitor, as a
crosscheck.
Your bios is what you should trust. I wouldn't worry about
the monitoring software. Even if you were at 2.14v you are quite
safe.
2.2v is he highest safe value for prolonged use. Though some
manufacturers will put them up to 2.3v, DDR2 in general is made
to handle it up to 2.2v. As long as your system is perfectly
stable you should be fine.
0.04 V doesn't make a difference. Most DDR2 can easily
handle 2.2V. My OCZ platinum is guaranteed to run at 2.2V.
Corsair is a top RAM manufacturer, so no worries."

Many thanks, Paul!

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On Thu, 04 Mar 2010 20:15:35 -0500, Paul wrote:

It still doesn't
tell us though, whether the motherboard supports EPP.

Does the re-setting (from presumably the default of AUTO) of:

DRAM Frequency -- 1066MHz
Memory Over Voltage -- 2.100000V

not indicate that it *does* support EPP?

(The supplier of this PC say they did not make any changes to the
BIOS settings - though I am pressing them on this point, as it was
they who fitted the 1066MHz RAM..)

I could probably suggest ways you could test for support
of EPP yourself, but at this point, why mess up your
system ?

If there was a method that would not irretrievably mess up my
system, I might be curious enough to try it!

Regards,
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Maurice Batey wrote:
On Thu, 04 Mar 2010 20:15:35 -0500, Paul wrote:

It still doesn't
tell us though, whether the motherboard supports EPP.

Does the re-setting (from presumably the default of AUTO) of:

DRAM Frequency -- 1066MHz
Memory Over Voltage -- 2.100000V

not indicate that it *does* support EPP?

(The supplier of this PC say they did not make any changes to the
BIOS settings - though I am pressing them on this point, as it was
they who fitted the 1066MHz RAM..)

I could probably suggest ways you could test for support
of EPP yourself, but at this point, why mess up your
system ?

If there was a method that would not irretrievably mess up my
system, I might be curious enough to try it!

Regards,

On thinking about it, I don't see any easy way to verify whether the
BIOS supports EPP.

I've been searching for evidence of EPP support, and generally
it seems to get mentioned in adverts for Nvidia chipset boards.
I suppose this is only natural, as Nvidia and Corsair were the
first two to support EPP. Other than that, I don't seem to see
it listed as a feature in the feature section of the manuals.

The thing is, if Vdimm is set to "Auto" in the BIOS, you have no
way of reading out the value it is using. You'd need a utility
of some sort, running in Windows, to figure it out. Or, you
could use a multimeter, and (somehow) figure out where to probe
to measure Vdimm.

My motherboard has a whole bunch of voltages that can be adjusted,
but only seems to have four voltages measured on the hardware
monitor. So I don't have a way to measure the actual Vdimm
delivered, using just the motherboard. I think I'd need
a multimeter, if the BIOS was set to "Auto", to figure out
what it was actually using.

The information exists. There is a hardware register somewhere,
that is used to control Vdimm, and that means there should be
a way to read it out. But if no one designs a utility to do that,
then it is going to be pretty hard to figure out.

Paul