Not all of my memory is showing up

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I'm trying to get an old A64 3500+ 939 (disabled Manchester) system up and running with two 256MB and one 512MB sticks of RAM, I can put any single module in any slot and it'll be recognized. The two 256MB stick in slots 1 and 2 (or 3 and 4) will get me dual-channel like it's supposed to. But if I use all three modules, then only the modules in slots 1 and 3 are recognized, and I get stuck in single-channel mode with either 512MB or 768MB or RAM, depending on the arrangement

So my question is this: Is this behavior due to some limitation in the A64 memory controller, or is it a problem with the motherboard?
 
Spooony said:
If the sticks ain't identical then your not going to see dual channel
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That's not true, but not getting dual channel isn't the problem that I'm concerned about. 512+256+256 = 1024... I'm only seeing at most 768MB when I use all three sticks.
 
When you place them in 256+512+256 it fail as well?
This is likely to be caused by mainboard, please tell us model.
 
Acer_Sheep said:
When you place them in 256+512+256 it fail as well?
This is likely to be caused by mainboard, please tell us model.
Click to expand...

An old Jetway A210GDMS-Pro. Slots 1 & 3 are Channel A, Slots 2 & 4 are channel B.

Any combination of two slots filled will work just as it's supposed to.


With slots 1, 2 & 3 filled, slot 2 isn't recognized
And with 1, 3 & 4 filled 4 isn't recognized

I didn't try 2, 3 & 4.. but I doubt it will make any difference.

EDIT: Just tried 1, 2 & 4, only slot one was recognized. And 2, 3,& 4 give me no memory error (which was expected).
 
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I asked model, type of your mainboard, motherboard in your PC you have those sticks installed in. But would be interesting what would happen if all 4 slots were filled. When you turn it on like this, it shows dual channel disabled on POST?
 
Acer_Sheep said:
I asked model, type of your mainboard, motherboard in your PC you have those sticks installed in. But would be interesting what would happen if all 4 slots were filled. When you turn it on like this, it shows dual channel disabled on POST?
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umm, I told you the model of the motherboard. Jetway A210GDMS Pro.

I also wondered how four stick would behave, but I've only got these three. I don't carry much DDR1 anymore.
 
Sorry got it now, seems ad system on [H] directed me to different site.

Seems your mainboard is not properly recongnizing sticks when attached to both channels, have you tried to update bios?
 
You have to have paired memory modules for dual channel otherwise it will run single channel and its acting as designed because you don't have paired modules you have 2 paired and 1 unpaired.
 
Falcon_CMH said:
You have to have paired memory modules for dual channel otherwise it will run single channel and its acting as designed because you don't have paired modules you have 2 paired and 1 unpaired.
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Again, that's not true. you only have to have the same amount of RAM in each channel.

As I said before, not being in dual-channel mode isn't what I'm concerned about... I would just fine running in single channel mode if weren't for an entire stick of RAM missing if more than two slots are populated.. The only thing I can do at this point is try to find some more memory and see if will work with four sticks. I just wanted to know if this was a quirk of the old 939 integrated memory controller or if the problem was my motherboard.


Acer_Sheep said:
Sorry got it now, seems ad system on [H] directed me to different site.

Seems your mainboard is not properly recongnizing sticks when attached to both channels, have you tried to update bios?
Click to expand...

It's got last BIOS available. I know it used to work with 4x512MB of DDR400, but that was years ago.
 
ryan_975 said:
Again, that's not true. you only have to have the same amount of RAM in each channel.
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I think that ended with the nForce 2 Ultra 400 chipset. Remember how channel 1 only had one dim slot, and channel 2 had two dim slots? You could upgrade your 2x256MB to 1GB with buying a 512MB for channel one, and putting your two 256MB in channel two.
 
Falcon_CMH said:
It is true believe it or not. And and you are having issues.
Click to expand...

Well, my sons' computers (one an AM2, the other an AM2+) tell me it's not since they've both run 1x1024 and 2x512 in dual channel mode at different points in time (one is still running that way today). The P5Q Pro i was using up until last night was able to run 3x2GB in asymmetric dual channel mode when I lost a 2GB stick to RMA it.


But if you don't want to believe me, here's what Intel has to say about it:

Dual channel symmetric mode is used when both Channel A and Channel B DIMMs are
populated in any order with the total amount of memory in each channel being the
same, but the DRAM device technology and width may vary from one channel to the
other.
Click to expand...
 
Falcon_CMH said:
OK then explain why your MB doesn't work in that config.
Click to expand...


If I could explain it, then I wouldn't have asked the question on here only to be told generally wrong information about an issue that I'm not concerned with. A configuration that is unsupported for dual-channel mode has always left the system single channel mode in my experience, not completely ignore anything plugged into the second channel.

So to rephrase my question, how can a motherboard cause the CPU's integrated memory controller to ignore modules when none of the slots are bad and all the modules test okay and are recognized individually or in any combination of two modules? If it's gone bad, then wouldn't any problems show up in a consistent manner (e.g. if slot 2 was bad, so nothing is slot 2 would ever work regardless of how the other slots were populated)?
 
Ryan_975 : I cant explain it either, I have an old HP system with an A64 3500+ 939 running right now as a utorrent machine on my home network with 2X256 in slots 1&2 and a single 512 in slot 3 so I don't think its the memory controller. I posted here because of the useless help you received from this award winning post...

Falcon_CMH said:
OK then explain why your MB doesn't work in that config.
Click to expand...

Ummm... The OP posted to ask a question and your help is for the OP to explain why it doesn't work? Weak, seriously weak... Seriously, why even bother posting in this thread?

Ryan_975 : If you PM me your address I'll send you a couple DDR sticks to test your system. I was cleaning up my office on my day off yesterday and found half a dozen sticks of mixed DDR and DDR2. I'll pay the postage if you want a couple to test your board, i'm not going to do anything with them.

Kroz
 
Kroz said:
Ryan_975 : I cant explain it either, I have an old HP system with an A64 3500+ 939 running right now as a utorrent machine on my home network with 2X256 in slots 1&2 and a single 512 in slot 3 so I don't think its the memory controller. I posted here because of the useless help you received from this award winning post...



Ummm... The OP posted to ask a question and your help is for the OP to explain why it doesn't work? Weak, seriously weak... Seriously, why even bother posting in this thread?

Ryan_975 : If you PM me your address I'll send you a couple DDR sticks to test your system. I was cleaning up my office on my day off yesterday and found half a dozen sticks of mixed DDR and DDR2. I'll pay the postage if you want a couple to test your board, i'm not going to do anything with them.

Kroz
Click to expand...

Wow, that's fucking awesome man. Thanks.
 
Look you don't have to rag on my I came here to help. All I said is if you ran a single module in one channel it would run single channel. Thats how most all IMCs are designed and what I have experienced. Now why it ignores your second channel with the memory stick is proably the memory is incompatible with each other in some way like speed, CAS etc. It really can't be the MB since the IMC is on the chip. And if the IMC supports it and is good the only left is the memory. Just using logic here.
 
Falcon_CMH said:
Look you don't have to rag on my I came here to help. All I said is if you ran a single module in one channel it would run single channel. Thats how most all IMCs are designed and what I have experienced. Now why it ignores your second channel with the memory stick is proably the memory is incompatible with each other in some way like speed, CAS etc. It really can't be the MB since the IMC is on the chip. And if the IMC supports it and is good the only left is the memory. Just using logic here.
Click to expand...

At what point did I ever say I expected a single stick to run in dual channel mode?

And we'll just have to wait and see if there is an incompatibility issue in a few days. I don't think there is since the 256 modules are identical, and the 512 will work with either of them in pairs. Now it may be that the BIOS isn't liking the different speeds and can't initialize the memory controller properly... but again we'll see.
 
I don't think the BIOS really plays a part other than setting speeds since it's an IMC. But like you said you'll see shortly with the kind offer of getting some extra memory to play with to debug it.
 
Falcon_CMH said:
I don't think the BIOS really plays a part other than setting speeds since it's an IMC. But like you said you'll see shortly with the kind offer of getting some extra memory to play with to debug it.
Click to expand...

Oh it plays a critical role in getting the system set up and going. The processor's IMC is not set up when it first boots up, so it has no idea that it even has any memory to do anything with. The BIOS has to get the IMC initialized before you can start using any of your memory. If you want to see how much the BIOS has to do to get your computer up and running, read the Kernel and BIOS developers guide that's AMD's published for their processors.
 
ryan_975 said:
Oh it plays a critical role in getting the system set up and going. The processor's IMC is not set up when it first boots up, so it has no idea that it even has any memory to do anything with. The BIOS has to get the IMC initialized before you can start using any of your memory. If you want to see how much the BIOS has to do to get your computer up and running, read the Kernel and BIOS developers guide that's AMD's published for their processors.
Click to expand...
Have to agree here, most peeps think bios is just diagnostic POST screen showing mem test and attached drives.
 
ryan_975 said:
But if you don't want to believe me, here's what Intel has to say about it:
Click to expand...

Since when does Intel have anything to say about AMD systems? Or is this one of those Intel Athlon 64 processors?
 
Met-AL said:
Since when does Intel have anything to say about AMD systems? Or is this one of those Intel Athlon 64 processors?
Click to expand...

If you want to pick apart my post and only consider the information that let's you make a stupid ass assumption.. be my guest.
 
Edit: nevermind. I've got the help I needed from the people who actually bothered to read what I was asking rather than going on to tangents that really didn't address my issue. So I'm done with this. So call me whatever names you want if it'll make you feel better about not having actually offered any help.
 
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