Bios says PC6400 running at 5300 on a P5WD2 Premium

[Richard E. Braunstein]

I spurged a few weeks ago and purchased an Asus P5WD2 Premium mobo
(with WiFi add on, as if it mattered) with matched pair of Corsair
PC6400 (2x512) DDR2 ram, and running in dual-channel mode.

When booting, the bios show it as PC5300. Anything is an improvement
over what this system replaced, but still, it is troublesome not to be
able to run this at its full potential.

I haven't a clue how to check the the latency which should be,
according to reports and on Corsair's website 5-5-5-12, nor can I find
anything in the bios to change or try.

Any clues or help would be much appreciated. Thanks in advance....

 

[Paul]

I spurged a few weeks ago and purchased an Asus P5WD2 Premium mobo
(with WiFi add on, as if it mattered) with matched pair of Corsair
PC6400 (2x512) DDR2 ram, and running in dual-channel mode.

When booting, the bios show it as PC5300. Anything is an improvement
over what this system replaced, but still, it is troublesome not to be
able to run this at its full potential.

I haven't a clue how to check the the latency which should be,
according to reports and on Corsair's website 5-5-5-12, nor can I find
anything in the bios to change or try.

Any clues or help would be much appreciated. Thanks in advance....

This is how I would start.

First, get a copy of CPUZ from www.cpuid.com . That will allow you
to verify what your system is doing, while you are in Windows.
I've had BIOS lie about how the system was set up (a possibility
if using early BIOS, for example), and a Windows utility is good
to use as a cross-check.

Next, in the BIOS, I would try (section 4.4.1 of manual):

AI Overclocking [Manual] - should cause other menu items to appear.
Performance mode [Standard] - will enable any performance feature
- do not use Turbo, unless you want a
crash at POST.

Now, you should see a "DRAM Frequency" item. There is a nice
table in your manual, where anything above DDR2-667 is marked
with an asterisk. It says "Provided for Overclocking Purposes
only", and that is because, as far as I know, DDR2-667 is the
current top JEDEC freqneucy ? I don't know if DDR2-800 is now
part of the standard or not.

The nice table in the manual, relates processor FSB to the
possible DRAM speeds. This table is basically showing you
what divider ratios are supported between the CPU clock
choice and the DRAM clock source. It looks like, for any
reasonable FSB frequency, you should be able to select DDR2-800
if you want.

In section 4.4.5 of the manual, the "Configure DRAM Timing By
SPD" setting exists. If you set that to manual, you could choose
settings other than 5-5-5 if your memory supports that. As to
whether this makes a difference to your overall performance,
look on Anandtech for some articles on DDR2 memory, to see
how much of an impact optimizing these settings would have.
While I haven't looked at those articles lately, my impression
is there is not much real world advantage to cranking DDR2
timing. Don't let that stop you from playing with it, though.
You paid good money for the opportunity to have those settings,
so by all means, try them out. Get a copy of memtest86+ from
memtest.org , and change the settings one step at a time,
test with memtest86+ for a couple of passes, to determine
just how much cranking the memory can take. By changing the
settings slowly, you'll be able to see the transition from
error free memory operation, to a few errors showing up, which
will tell you how much room you have to adjust timings.

Also, pay attention to whatever voltage rating your Corsair
memory has. It could be, that at the higher memory frequency
settings, the memory might need a bit more Vdimm applied. As
I don't have or use DDR2 memory, I have no idea what boost is
appropriate. It could be, as little as an extra 0.1V is
enough to help. On the Corsair datasheet for your product
(downloadable from the corsairmicro.com website), they may
mention what the acceptable upper limit for voltage is.

http://www.corsairmicro.com/corsair/xms2.html

"Tested at the low latencies of (5-5-5-12-T1) at 1.9V"

Paul

 

[Richard E. Braunstein]

I spurged a few weeks ago and purchased an Asus P5WD2 Premium mobo
(with WiFi add on, as if it mattered) with matched pair of Corsair
PC6400 (2x512) DDR2 ram, and running in dual-channel mode.

When booting, the bios show it as PC5300. Anything is an improvement
over what this system replaced, but still, it is troublesome not to be
able to run this at its full potential.

I haven't a clue how to check the the latency which should be,
according to reports and on Corsair's website 5-5-5-12, nor can I find
anything in the bios to change or try.

Any clues or help would be much appreciated. Thanks in advance....

This is how I would start.

First, get a copy of CPUZ from www.cpuid.com . That will allow you
to verify what your system is doing, while you are in Windows.
I've had BIOS lie about how the system was set up (a possibility
if using early BIOS, for example), and a Windows utility is good
to use as a cross-check.

Next, in the BIOS, I would try (section 4.4.1 of manual):

AI Overclocking [Manual] - should cause other menu items to appear.
Performance mode [Standard] - will enable any performance feature
- do not use Turbo, unless you want a
crash at POST.

Now, you should see a "DRAM Frequency" item. There is a nice
table in your manual, where anything above DDR2-667 is marked
with an asterisk. It says "Provided for Overclocking Purposes
only", and that is because, as far as I know, DDR2-667 is the
current top JEDEC freqneucy ? I don't know if DDR2-800 is now
part of the standard or not.

The nice table in the manual, relates processor FSB to the
possible DRAM speeds. This table is basically showing you
what divider ratios are supported between the CPU clock
choice and the DRAM clock source. It looks like, for any
reasonable FSB frequency, you should be able to select DDR2-800
if you want.

In section 4.4.5 of the manual, the "Configure DRAM Timing By
SPD" setting exists. If you set that to manual, you could choose
settings other than 5-5-5 if your memory supports that. As to
whether this makes a difference to your overall performance,
look on Anandtech for some articles on DDR2 memory, to see
how much of an impact optimizing these settings would have.
While I haven't looked at those articles lately, my impression
is there is not much real world advantage to cranking DDR2
timing. Don't let that stop you from playing with it, though.
You paid good money for the opportunity to have those settings,
so by all means, try them out. Get a copy of memtest86+ from
memtest.org , and change the settings one step at a time,
test with memtest86+ for a couple of passes, to determine
just how much cranking the memory can take. By changing the
settings slowly, you'll be able to see the transition from
error free memory operation, to a few errors showing up, which
will tell you how much room you have to adjust timings.

Also, pay attention to whatever voltage rating your Corsair
memory has. It could be, that at the higher memory frequency
settings, the memory might need a bit more Vdimm applied. As
I don't have or use DDR2 memory, I have no idea what boost is
appropriate. It could be, as little as an extra 0.1V is
enough to help. On the Corsair datasheet for your product
(downloadable from the corsairmicro.com website), they may
mention what the acceptable upper limit for voltage is.

http://www.corsairmicro.com/corsair/xms2.html

"Tested at the low latencies of (5-5-5-12-T1) at 1.9V"

Paul

Many thanks for your assistance. You know, I've read that manual from
cover to cover at least a half dozen times over the past month. Since
I am not an overclocker I never changed the AI Overclocking feature
from its default state of 'Auto', until you suggested doing so. This
of course brought up the subset features you described. Once I set it
at DDR2-800, which is really not overclocking, as these chips are
native to that speed, my PC booting now shows the true value of the
Corsair twins as what they are, that being PC6400.

Now that that is settled, you've certainly tweaked my curiosity
further and plan to do some more exploring. One of the features I'd
like to experiment with is the ability to overclock directly through
windows which this motherboard supports. Is this a feature that is
available to other high motherboards or is this something new?

I'm just a plain old ordinary vanilla type of user, but this seems
like it can be somewhat fun and amusing to pass the time while our
outside temperatures range between 115 and 120 daily.......

Much thanks and kindest regards,
Richard

 

[Paul]

Many thanks for your assistance. You know, I've read that manual from
cover to cover at least a half dozen times over the past month. Since
I am not an overclocker I never changed the AI Overclocking feature
from its default state of 'Auto', until you suggested doing so. This
of course brought up the subset features you described. Once I set it
at DDR2-800, which is really not overclocking, as these chips are
native to that speed, my PC booting now shows the true value of the
Corsair twins as what they are, that being PC6400.

Now that that is settled, you've certainly tweaked my curiosity
further and plan to do some more exploring. One of the features I'd
like to experiment with is the ability to overclock directly through
windows which this motherboard supports. Is this a feature that is
available to other high motherboards or is this something new?

I'm just a plain old ordinary vanilla type of user, but this seems
like it can be somewhat fun and amusing to pass the time while our
outside temperatures range between 115 and 120 daily.......

Much thanks and kindest regards,
Richard

There is AIBooster, a Windows program that uses the ATK0110 ACPI
driver, to change settings while in Windows. I don't know how
stable that method is, and personally would not use it. (I
prefer doing it via the BIOS, disconnecting the hard drive,
using a Knoppix boot CD, so there is no chance of corruption
while overclocking. Then, test for stability at the new clock,
using programs like memtest86+ and Prime95 (linux version),
and when all looks good, reconnect the hard drive and boot
Windows.)

Here is an early version user manual:
ftp://ftp.asus.com.tw/pub/ASUS/mb/sock478/p4p800/AIBooster_u.pdf

Most of the benefit will come from increasing the core frequency,
and with the locked multiplier on the processor, that means
cranking the CPU clock. In terms of headroom, Prescott 90nm
processors can go over 4GHz now, and how much further than that
depends on the cooling system. Some people use two stage refrigerator
systems for such experiments. Air cooling will give a bit
tamer overclock. There are all sorts of threads like this:

http://www.abxzone.com/forums/showthread.php?t=79450&highlight=prescott+overclock

Have fun,
Paul