M3A79-T Dlx Problems

[Dolk]

Right now I'm having problems with this board on multiple levels.

One part that concerns me is that I can't use Dual Channel memory any more. Or at least it seems that way. Using my [chewed up] 940, memory must stay in Single Channel. Using a Regor 240, memory can be in dual channel. Using my new 1090T, it must stay in Dual channel. Any Ideas on this?

Note that I am using a beta bios for the 1090T, but for the 240, and 940 they were tested on the stable 1501 BIOS.

On both accounts for the 1090T and 940, I can boot, sometimes POST, 5% chance to get into an OS. No beeps will be played as well.

MemTest says that it works fine and will work on Dual Channel. (MemTest was performed on a different computer with the same memory that is in my computer now)

 

[QuietIce]

Did you mean?

Using my new 1090T, it must stay in Single channel. Any Ideas on this?

The only thing I can think of that might be difference is the cpuNB voltage.

There's also no L3 with the 240 but I don't see where that would make a difference unless the board is that touchy about the IMC. I'd bet the 240 IMC is a different configuration than the Phenom II/Thuban. Still can't imagine how that could make a difference - but with busted hardware who knows ...?

 

[Dolk]

I just don't understand how the motherboard can be the culprit of Dual Channel failure. CPU, and Memory, that makes sense.

Also CPU-NB voltage is the same. At least the Thermal And Power Documentation says so at 2000 Mhz.

 

[QuietIce]

You set the cpuNB voltage to be the same? Just checking - default NB voltage is probably different for those CPUs - at least it is for the Phenom II X2's over the X4's.

Doesn't power come from the board as well as the physical connection between the CPU and RAM (with maybe a chip of some kind between them)? I don't know the details of the IMC-RAM connections so I'm just guessing there but I'm sure the power comes from the board.


I can't pin it down and, as an engineer, you'd never understand my ideas about it. When I was OC'ing and playing with settings on the 940BE I kept getting the sense it was as much about balance as it was about specific voltage, timings, etc - more of how they worked together than the specific details of any one component. I can't explain it any better than that - call me crazy ...

 

[Dolk]

No, I know exactly what your talking about.

 

[QuietIce]

No, I know exactly what your talking about.

I think somewhat like a (civil) engineer (shhh, don't tell anybody) even though I never had any formal training in it (but surveying 25 years you learn a LOT ). The concepts come naturally to me but I've seen so many in engineering that have degrees and licenses but are worse engineers than I am (in a lot of ways) because they just have no feel for the work - they're just doing it by rote from what they were taught. When I say something to them about "things not looking right" they think I'm nuts because I have no numbers to back up my statements. I'm glad to hear you're NOT one of those ...

 

[Dolk]

Does the HyperTransport work between the IMC and Memory? If not, whats the bus that is there?

 

[QuietIce]

The HTL only connects the cpuNB, NB chipset, and SB - it's not involved in system memory at all except as it passes some data (destined for system memory) from the system to the cpuNB but the cpuNB/IMC takes it from there.

I can't remember seeing anything about the "RAM bus" and always assumed it was controlled through the IMC - but I'd still think there would need to be some type of interface between the IMC and the RAM sticks ...?

 

[Dolk]

Yeah thats what I'm trying to figure out.

BTW, your HTL header is in the CPU. Its on a different part of it.

 

[QuietIce]

Yeah, after reading more I remembered why I had thought it almost has to be on the CPU. Opterons (NOT the s939 1xx series) have three HT Links, not just one. The other two are for intra-CPU communications on multi-processor systems. But they could put that into the NB chipset as well since multi-processor systems have different chipsets than consumer rigs.


Anything I should read to see how that works? In my searching I've never been able to find any proof that it was on one or the other - just vague hints here and there, which seem to conflict ...

 

[trents]

I just don't understand how the motherboard can be the culprit of Dual Channel failure. CPU, and Memory, that makes sense.

Also CPU-NB voltage is the same. At least the Thermal And Power Documentation says so at 2000 Mhz.

You wouldn't think so but my experience is that dual channel problems are sometimes a bios issue and not a hardware issue.

 

[QuietIce]

Just curious - have you tried the off chance of resetting BIOS with one stick of RAM ...?

 

[Dolk]

No I haven't, I'll have to try that.

about the HT thing, I'll have to look up the section I read last week. There is a place where it talks about it for like one sentance and thats it.