Dual channel problems

likwid

likwid

likwid

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Hi

I recently bought some secondhand Geil value RAM 2 * 1gb, apparently a dual channel kit.

The ram will only work when both sticks are used in different channels. A single stick wont work, neither will two sticks in dual channel configuration. It'll post but windows boot returns missing file errors.

I know i should run memtest but i don't have any cdr's lying around at the moment. Anyone have a likely explanation for this scenario?

Cheers
 
Hi

Thanks for replies.

I'll look into usb drive, i didn't know you could do that.

The cpu is not overclocked and bios settings are default. I have my old geil value 2*512 dual channel which work absolutely fine.

edit - I don't think my motherboard allows booting from usb. It's an Asus A8N-VM CSM.
 
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Yeah according to the specs for Geil Value 2 x 1GB it should be CAS 3. The rest looks ok and would probably work fine with very cheap generic ram except maybe the Max Async Latency might be more stable with it at 8 or 9 and the Read Preamble higher too maybe even all that way to 9.5.

Hopefully you can set it to CAS 3 in the bios and it'll work properly.

Also your motherboard's bios is unlikely to contain options for changing MAL or RP but maybe at CAS 3 it'll auto slacken MAL and RP.

EDIT: If your bios lets you change the Drive Strength then change it to Weak to see if that helps and also check the bios to see if you can change it to 2T timings to see if that also helps.
 
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Also you might want to update the motherboard to the latest bios if you haven't already as it's possible it'll have better memory support.
 
Just looked at your boards manual and it does allow setting MAL and RP! Nice for a mATX board to have such options. :)
 
Hmm. I was excited, thinking this was all fixed but i set cas to 3 in bios, fitted the 2 gig ram and tried booting windows, only to find the same problems, the system would reboot every time.

OK. This is kinda odd.

http://www.likwid.f2s.com/images/mem2.jpg

I set the cas timings to 3 in the bios, yet this is what's reported..

The bios is the latest. The bios settings are over my head to be honest.

Any thoughts?
 
With the 2 x 1GB fitting in dual channel mode when you boot the PC can you go into the bios to change settings without it crashing?

If you can get into the bios change it to CAS 3 and also change the Max Async Latency to 9 and Read Preamble to 9.5 and leave everything else on Auto and then see if it boots into windows.

EDIT: If it fails go into the bios again and change it so it's using 2T timings (your board has this option labelled CMD-ADDR Timing Mode).
 
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I just changed cas in bios back to auto and a64tweaker still reports it as 4.5.

I'll try out those settings and report back, although it might not be tonight as my girlfriend is coming shortly and she'll go nuts if i'm doing computer things.

Thanks very much for your help, it's really appreciated!
 
**It worked**

**It worked**

Thanks so much my friend, i'm very, very happy!! I'd never of known this stuff.

Tell me one more thing though. This is in know way indicative of a prblem with the ram or the motherboard, and performance wont be lessened at all by the changes made?

Cheers!!
 
There'll be a slight decrease in speed if all you've done is change MAL to 9 and RP to 9.5 but it's really not much at all and if you needed to also change to 2T timings it's again only about a 1-3% benchmark loss.

It's unlikely the memory is faulty it's more likely the motherboard just doesn't know to set the right parameters to get it to work with stability. If you want to check the memory really does work fine with the tweaked settings you should run the Prime95 Blend test for at least a few hours.

Also you might want to experiement with MAL and RP for example MAL at 8 will also probably work and RP lower than 9.5 might also work (probably best to leave it at 9.5 though as it can take a fair bit of testing to find out if lower than 9.5 will work).

I suspect having 2GB of memory will make much more of a difference to you compared to 1GB even if it is using slightly slacker memory timings so just finding some that work is probably enough rather than finding the tightest settings possible.

I'm glad you hopefully have it all sorted anyway now mate as I know how much of a pain it is to have memory that should work at stock settings but doesn't! :)

EDIT: Was it the MAL and RP or those two and the 2T timings setting that got it to work?
 
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Also the S&M memory test is good at detecting memory errors. It's what I used to find out that having RP lower than 9.5 caused errors on my system.
 
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