Re: Bios says PC6400 running at 5300 on a P5WD2 Premium

On Sat, 13 Aug 2005 03:50:43 -0400, nospam@xxxxxxxxxx (Paul) wrote:

>In article <dgoqf11p9cgr3ufdc1bdcf99ju55me7t0j@xxxxxxx>, Richard E.
>Braunstein <whoizzy@xxxxxxxxxxxxx> wrote:
>> 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 . 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
> , 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 website), they may
>mention what the acceptable upper limit for voltage is.
>"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,


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