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Asus P5W DH Deluxe & Twin2x2048 PC8500C5


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Am I the only one here who can't get the Twin2x2048 PC8500C5 to run at their rated speed/timings on the P5W DH Deluxe motherboard.

I simply can't get it to run stable at DDR 1067MHz (1:2)

How much voltage am I supposed to give the modules at their rated speed/timings? I've tried 2.2V but no luck.

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Am I really the only one?


Ok, I finally got the time to test the memory with memtest165.


My TWIN2X2048-8500C5 hits the wall at 1042MHz 5-5-5-15. memstest runs for approx. 5 sec. and the errors just continues on and on.


The best setting I can run these modules at, is 999MHz 4-5-5-15. That suckz, not exactly what I expected for these very expensive modules.


I run the modules at 2.2V.


Are these bad parts?


Or, should I return them(14 day return policy in Denmark), and get the TWIN2X2048-PC6400C3 modules instead?


According to Anandtech.com, PC6400C3 should be able to run even faster and with better timings.



My current sys. spec.:


Intel Core2 Duo E6600 @ 3.0 (9*333)

Corsair Twin2x2048-PC8500C5 running 999MHz *(2:3) 4-5-5-15

Asus P5W DH Deluxe

Gigabyte 7950GX2

Enermax Liberty 500W



My goal was, but not possible:

Intel Core2 Duo E6600 @ 3.2GHz (9*356)

Corsair Twin2x2048-PC8500 running 1067MHz *(2:3), RATED SPEED(WHAT I PAID FOR)


*The 2:3 is the divider for PC800 when running 266FSB


If you are about to ask me, if I can run 1:2 divider with FSB at 266, nope not possible either.

So with everything at stock speed, I'm NOT able to run a PC8500 system.

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I have a very simaler setup


Intel Core2 Duo Extreme Edition X6800

Corsair Twin2x2048-PC8500C5

Asus P5W DH Deluxe

EVGA GeForce 7900 GTX 512MB GDDR3

Tagan TG1100-U95 1100W ATX2.01 Turbojet Quad SLi

Creative Sound Blaster X-Fi Elite Pro


Its been over 3 years since i built a pc .... was told this was the best mem for this mobo ....... so i would be very interested to see if there is an answer to your problem :):

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Well I have a similar problem.


P5W DH Deluxe

Core2 6600

2x CM2X1024-6400C4


I have tried everything and this RAM simply will not run stable at the rated speeds of 2.1v


Most stable setup I have been able to get so far is to use the BIOS overclocking at 1333FSB DDR2667, even that's had a few issues.


Every other manual config I have tried fails Prime very quickly or reboots the machine.


So far I am not very happy with this RAM.

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RAM Guy, thanx for the reply.


OK! That really surprises me!

What about all the websites who reviewed the 8500C5 dimms, they where able to hit speeds around and beyond 1100MHz. Are they lying? Most of them are using 975X based P5W DH Deluxe...

Heres an example:



And those sites made my final buying decisions.


So what about the 6400C3 dimms? Aren't they able to hit the 1066MHz on 975X? Check the link before answer that question....


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Just verified with our LAB guys and ASUS peak on this motherboard is 1000MHZ><. You may want to email the reviewers on how they got their results, but this is our straight up honest answer.


CPU Ratio                 | Memory Speed | Best Memory Timings / (Voltage) 
Highest Mem Speed (1:2)   |    1104 DDR2 |     5-5-5-15  2.35V


by voiding the warranty apparently :)

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simple fact Asus P5W DH needs a bios update to open up additional memory timings available in memset as the key to clocking memory and fsb higher in async dividers for core 2 duo is tRFC and tRD values and some more vMCH and vdimm volts in some cases.


take a read of my testing on P5W DH that Asus provided me at http://i4memory.com/showthread.php?t=3034 and divider testing http://i4memory.com/showthread.php?p=47177#post47177


good news is Asus are working on exactly such a bios to open up additional memory timings like they did for P5B DX board :)


I have no probs taking PC6400 Micron D9GMH based memory to 501-513mhz 4-4-4-8 at 2.2v or 540mhz 4-4-4-8 or 555mhz 5-5-5-5 at 2.4v on P5W DH with E6600 or E6700 after tweaking memset timings for tRD and tRFC



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This board really needs bios work as eva2000 posted.


The memory qualification info for the Twinx/XMS2-8500/C5 posted here


shows 1T/2T: 2T


On the asus p5w-dh when in by spd mode the cmd rate is always set to 1T per sisoftware sandra 2007 and same in manual timing mode with no way in in bios to change it.

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There seem to be many problems overclocking this board over those frequencys like the board is changing its bootstrap (not sure yet on what this is) as reported on the xtremesystems forum.


Maybe have a look there and/or post your problem, odds are the ram is fine but as yet with high FSB the board is doing something and trying to be clever which is causing the problem.


PS I take it disabling Hyper Path 3 doesnt make any difference?



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my question is what is the best ram to use with this mobo bearing in mind i am not overclocking just want it to be quick without muckin about with it .....as i have Rma'd my Corsair Twin2x2048-PC8500C5 and my knowlege with bois settings isnt good ,,,,,,, so if someone can recomend the best ram for the 6800 extreme and the P5W Dh Deluxe it would be realy great :D:
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my question is what is the best ram to use with this mobo bearing in mind i am not overclocking just want it to be quick without muckin about with it .....as i have Rma'd my Corsair Twin2x2048-PC8500C5 and my knowlege with bois settings isnt good ,,,,,,, so if someone can recomend the best ram for the 6800 extreme and the P5W Dh Deluxe it would be realy great :D:


Judging by the responce on here it doesnt look like i am going to get any help

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I too have a new system with the E6600, P5W and corsair PC2-8500 ram (2GB). I have the system running stable at 3.645GHz (405 FSB x 9) with air cooling at 38°C idle. I can only get the ram up to around 820MHz 4-4-4-8.


If I try to put it at 1066MHz (which it's rated at and all of the reviews I've seen do it), they system won't POST. This is at BIOS set memory timings, but loosening the timings doesn't seem to help.


/* Start kicker */

The system runs fine at the stock 266MHz FSB with the ram at 1066MHz 5-5-5-15 (BIOS set).

/* End kicker */


So, I see that the board can run the ram over 1000MHz, I just don't get why, when the CPU/FSB is overclocked and I have the ram multiplier set correctly, like at 366x4 it won't run at 1066MHz (even with ramV set to 2.4V).


Is there a divider issue with this board I haven't come across in the forums/literature/reviews?



Am I running out of system power? I have the TP-II True Power 550W PS.

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the motherboard ram combo isn't even listed there... I don't understand. I'll say it again. My ram runs at 1066MHz at stock FSB but when I divide the FSB clock down for the RAM as I overclock the system to 405Mhz, I can only get it up to 1:1 810Mhz. If I put it at the BIOS setting of "DDR2-1025MHz" the system won't POST.


So in summary... the ram DOES do 1066 but only at 266FSB. What settings on the MB is limiting the usage of the ram at 1066 when the FSB is divided?


Make sense?

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  • Corsair Employees
NO, you have to run the CPU and memory 1-1 and if your CPU will not over clock that well U will not be able to reach the target frequency. Please go back read my previous posts in this thread! And look at the same type of MB's using these modules your specific MB may not have been tested because we know this chipset will not consistantly run at these speeds!
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Well, I seems to have a bit more luck in this one.

I got my system to post and runs fine at DDR2-1067 with the specified specs (5-5-5-15-2T 2.2v)


It seems to run fine and all.


THEN after playing games on it for several days, I ran memtest to confirm that the whole system is ok to actually do some work on.

To my surprise, it always locks up on around 32-35% memtest.


I'm no tech savvy here so I don't normally overclock, but I DO want the RAM to run at their specified speed.

So tell me here... can I up the voltage a tiny bit without voiding the warranty?


I can't tell how I'm supposed to check the temp on the RAMs.

I'd imagine they run a bit hot since I don't have that much air circulation within the case (due to water cooling). Although I'm quite sure there's enough air blowing over the top of the RAM area to cool em off ok (there's a 120mm fan on the back blowing air into the case).

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Hmm... I just left most of the options on default.

The only things I changed is

AI Overclocking >> Manual (so I can set the DRAM frequency)

CPU frequency left on default (266)

DRAM frequency >> DDR2-1067


Then in the Chipset settings

Disabled the set DRAM by SPD

so I can specify the CAS-RAS and all those things to spec (5-5-5-15-2T)

and set the voltage to 2.2v


Other other settings I changed would be in relation to storage

ACPI and enabled all the SATA things in IDE configuration.


That's about it.


BTW, I just tried your suggestion (disabling the USB legacy support). Well, it may well be 'one' of the cause of the crash. It now have:

Unxepected Interrupt - Halting

at 34% completion of the 1st pass


I'm using the latest memtest86+ that's supposedly support conroe.


I'll post the whole BIOS setting a bit latter if that'd help.

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Here's the BIOS changes I made:


IDE config

- configure SATA as >> AHCI

- ALPE AND ASP >> Enabled

- IDE detect timeout >> 5



- JumperFree config

- AI Overclocking >> Manual

- CPU freq >> 266

- DRAm freq >> DDR2-1067Mhz

- Memory voltage >> 2.20v

- MCH voltage >> Auto (left on default. Should I change this?)


- USB config

- Legacy USB support >> Disabled


- Chipset

- Configure DRAM timing by SPD >> Disabled

- CAS >> 5

- RAS >> 5

- RAS to CAS >> 5

- RAS activate to precha >> 15

- DRAM write recovery >> 2


- Onboard devices config

- Jmicron SATA/PATA controller >> Enabled

- Jmicron conrtoller mode >> Basic

- JMicron SATA/RAID bootrom >> Enabled



- ACPI 2 support >> Yes

- ACPI APIC support >> Enabled



The rest of the configurations are not changed. All left on their default, which is mostly 'Auto'

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