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Design Flaw in Dominator 8500 C5D with Asus P5Q Pro?


andypiper

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I am awaiting my 4th replacement set of corsair RAM for this motherboard. I have had 1 set of 2x2gb TwinX 6400C5 and 2 sets of 2x2gb Dominator 8500C5D fail on me now. It seems unlikely to me that I am just that unlucky and wonder if anyone has any suggestions as to what might be the problem. I used to buy Corsair RAM for the presumed quality, but this issue is making me rethink my buying decisions.

 

The first set of RAM (TwinX) failed after about 3 months. Memtest was clean but the PC would no longer suspend without crashing on resume. Also the C1E state could not be enabled on the processor without hanging windows. I originally replaced the MB and Processor thinking these were the problem, but the problem persisted until I changed the RAM.

 

The second set of RAM (Dominator v2.1) failed after two months. This time memtest came up with red ink for one of the sticks. I immediately replaced and all was ok. I installed extra cooling in the PC just in case this was affecting the RAM, but the sticks felt cool during operation.

 

The third set (Dominator v2.1) failed after just a month, memtest was clean this time but applications would crash after a while and after that the whole PC would go into BSOD.

 

My PC is on all day and is suspended at night (S3), i.e. I never switch it off fully. I am wondering whether this behaviour could be contributing.

 

Is it just me, or is there some deeper problem here? Both these RAM types are listed as supported for this MB by Corsair.

 

Any help appreciated!

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And with that CPU that you have listed the fastest you can run the memory would be DDR800 unless you over clock the CPU.

 

Now I am confused. So you are saying that the fact that the FSB is 1066Mhz is bad? The MB shows the FSB strap as 1:2 with the memory frequency as 1066Mhz. Why can I only run it at 800Mhz? When I set the RAM frequency in the BIOS to 1066Mhz is it indeed overclocking the CPU or having no effect? Every info utility I try says the CPU is running at stock speeds and the RAM also.

 

To be honest I currently don't care what speed it runs at as long as it keeps working!

 

Your input appreciated!

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The CPU you have is a 1066 FSB CPU my mistake, was thinking it was a 800 FSB CPU. With Intel chipsets you cannot run the memory frequency faster than the CPU FSB.

 

Even then I thought that the actual memory frequency on the bus side was 1/2 that of the rated speed (b/c its double-pumped) - hence the 1:2 FSB strap in my scenario, even though logically you would expect it to be 1:1. But I digress.

 

Does the memory pass http://www.memtest.org one at a time with http://www.memtest.org at the tested settings with Legacy USB Disabled?

 

With the latest failure it passed 3 runs of memtest, but my experience is that this is not indicative that the memory is actually ok - only once, out of 3 failed sets have I had memtest actually give errors. The first set passed memtest but gave the errors I described, I ran with one stick and all was fine, tried the other and the problems reappeared - which seemed pretty indicative.

 

This time I RMA'd it straight away, I have wasted too much time already rebuilding my PC with different components to isolate the problems, and its always been the memory :).

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We can get them replaced but that type of error would suggest it may not be the memory.

 

Ok, I will update this thread when I receive the new sticks. I'm fairly confident that everything will then be fine for a while. My reason for posting is to try and find out whether there is some other root cause to this problem.

 

Incidentally the procedure listed here http://forum.corsair.com/v3/showthread.php?t=54052 ask the DRAM speed to be set to 800Mhz. Is this really right? What about other motherboards using different chipsets that you have certified (like mine) what are the required settings? Or is it simply enough to set 1066Mhz, 2.1v and let the EPP settings do the rest?

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Your MB does not support EPP and the listed settings are on a MB that does not support DDR1066 and yes if you have problems I would try over clocking the CPU and running the memory at DDR800 if you have a 1066 FSB CPU, but if you have a 1333 FSB CPU the MB should have native support for DDR1066 memory .
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So can I ask - what would destroy the RAM like this? I have seen articles on the net which indicate that the P5Q Pro overvolts memory by 0.08 volts. Is this likely to damage things? Would getting too hot damage the memory? Seems like those are the only two things that should have any permanent effect, and even then I thought the JEDEC spec said memory had to survive up to 2.4v w/o permanent damage.
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The JEDEC Spec for DDR 2 memory calls for 1,8 Volts +- .11 Volts!

 

Not sure why I am doing this, but http://www.jedec.org/download/search/JESD208.pdf p55, table 15, although interestingly max w/o damage is shown as 2.3v there.

 

Also max operating temp is 85 oC so it seems unlikely that this is my problem.

 

Finally Asus says 128Mb (MegaBIT) chips aren't supported, which some people on the net seemed to think was a problem, but 2GB sticks use 16 x 128MB (MegaBYTE) chips, so that isn't the issue.

 

I am currently running with a spare stick of corsair 1MB C4 w/o any issues so it certainly IS the memory.

 

My conclusion thus far is that either the specific chips used by Corsair are incompatible in some way with this board, or that the board in general is a memory trasher. For now I am assuming it is the former and have ordered a competitors 4GB kit while waiting for my RMA'd kit. Time will tell...

 

andy

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From your link

VDDQ Supply DQ Power Supply: 1.8 V +/- 0.1 V Page 11

And if the modules will run one at a time but not in D/C that would suggest some other problem with the MB or chipset and I would get it replaced. Have you tested the modules in the other two slots and one up and if so what were the results?

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From your link

 

And if the modules will run one at a time but not in D/C that would suggest some other problem with the MB or chipset and I would get it replaced. Have you tested the modules in the other two slots and one up and if so what were the results?

 

New memory arrived. Plugged it in and everything is working ok again (1066Mhz in DC). So the memory definitely had failed. I am now running with some competitor's memory (my RMA'd dominator is running my Wife's machine ready to be used should the new memory fail as well). Interestingly, they claim you should run the DRAM voltage as low as is stable to preserve the life of the chips, since the rated voltage represents the highest needed on a range of motherboards. So I am running with 1.82v, which if you believe the 0.08v overvolt for the P5Q Pro == 1.9v. Everything appears to be running just fine, I ran memtest for a couple of hours and it completed without problems. So I slightly wonder whether the overvolt is more extreme than the rumours give credit for.

 

Also I am wondering whether its possible that the PSU is spiking when the system comes out of S3. Is this possible/likely (PSU is new 500w EarthWatts) ?

 

The new memory has some kind of overvolt protection, so if it fails I guess I am out of ideas. Maybe I will buy a new PSU just for the hell of it. Goodness knows I have thrown enough time and money at the problem already.

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Also I am wondering whether its possible that the PSU is spiking when the system comes out of S3. Is this possible/likely (PSU is new 500w EarthWatts) ?

 

I have convinced myself that even though this PSU is new and adequate for the system it is probably not consistent with the level of relaibility I am looking for, so I have ordered a Corsair 650TX

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  • 2 months later...
I have convinced myself that even though this PSU is new and adequate for the system it is probably not consistent with the level of relaibility I am looking for, so I have ordered a Corsair 650TX

 

Well after another 4 months my replacement set of Dominator 8500 has failed yet again. This time it's in a different computer with a different motherboard and different PSU (clocked at stock speeds - 800Mhz - and voltages - 1.8v!). Failure mode is the same as before - 100's of errors in memtest86 and windows thus failing to boot in multiple different ways.

 

I have asked for - and received - a refund from my supplier. I am done with Corsair I'm afraid. 4 sets failing in different rigs over similar timeframes is no coincidence I'm afraid, and nothing to do with the Asus mb or PSU.

 

Meanwhile my 1066Mhz 0*Z continues merrily along. I'll let you know if it fails too, but I don't think it will...

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