Thursday, February 12th 2009

Phenom II AM3 Plagued with DDR3-1333 Issue

Barely a week into the introduction of the DDR3-supportive AM3 socket CPUs, the processors seem to be having design flaws. This, as circulated by AMD in its revision guide document for the 10h family of processors (found here, page 80). The issue, as described by AMD, centers around the DDR3 memory sub-system. On machines with more than one PC3-10600 (1333 MHz) memory module populating a memory channel, the users may experience unreliable operation. The company does not get into the specifics of the symptoms. This issue however, does not affect systems with a module per channel (one or two modules installed in the motherboard), and only those with three to four modules installed.

The AMD K10 memory controllers on AM3-socket processor provide a 128-bit wide memory interface (with DRAM Ganged mode enabled), which amount to two 64-bit wide memory channels. On most motherboards, four DIMM slots with two slots sharing a memory channel are present. With this issue, one is not recommended to use more than one DDR3-1333 memory module per channel. AMD recommends a quick fix for the issue for systems using more than one DDR3-1333 module per memory channel: to manually specify the memory to run at 533 MHz (1066 MHz DDR), and accordingly set DRAM timings. As a little compensation, one can tighten DRAM timings with the drop in frequency. AMD will fix this issue in the next stepping (sub-version) of the CPUs. The "x-factor" with this erratum revolves around DRAM voltage, a significant factor. One might note AMD saying "the processor memory subsystem may exhibit unreliable operation over the allowable VDDIO voltage range", which leads us to think if there is a potential workaround with adjusting the DRAM voltage beyond the allowable range (read: over-volting the memory). We hope to hear more from AMD on this.

UPDATE (02/13): AMD replied to the report, saying that work is in progress toward fixing the issue. While not getting into the specifics, AMD indicated to us that apart from addressing the issue, the company is also working toward something "which will make you ‘feel cozy’ about the DDR3 support". The statement is ambiguous, and is best left uninterpreted at this point in time.
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105 Comments on Phenom II AM3 Plagued with DDR3-1333 Issue

#1
TheMailMan78
Big Member
DOM said:
:laugh: i think this thread needs to be closed already ppl getting mad for no reason
Come on DOM! Binge and I are already starting a riot! We got bagels!

I don't know why people are so up in arms about this. Its a first revision people! GET OVER IT!
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#2
btarunr
Editor & Senior Moderator
Updated.
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#3
cdawall
where the hell are my stars
swaaye said:
Or not work at all. See DFI nF4 Ultra-D. It would see only one pair no matter what I did with it.

Running 4 DIMMs is always a bitch. My Gigabyte P35-DS3R mobo automatically cranks the latency behind the scenes and needs more MCH volts. This isn't some modern revelation either. You can wander back in time to the days of Pentium and K6s and see that loading up all banks on the mobo will result in the need to turn down the latencies. More DIMMs/SIMMs = more difficulties in signal integrity.
i have noticed the same on my ECS P45BE, p5q-pro, K9A2 platinum, K9A platinum and crosshair II formula

DaedalusHelios said:
I have had many Gigabyte boards based on the P35-DS3R:

EP35C-DS3R x2
P35C-DS3R x2
P35-DS3R
EP35-DS3R

None of those needed any extra volts at MCH and they have mild OC's. I still have two in my house. Thats the most of the same series I have ever had. Funny thing you use that as an example being one of the best OC'ers of their time for the money. A few of those had 64bit Vista and 8GB of RAM like the one I gave to my GF. It had no issues that I have seen. :wtf:

I think your issue is the RAM you used. Its probably not on the Supported memory list. Common mistake really.
no using ram not on there stupid supported list makes no difference. 4 dimms stresses every mem controller drop max FSB clock alot. look on XS and find me a 600+ FSB clock with 4 dimms populated. there wont be one because its stresses the controller.

DaedalusHelios said:
People have been buying these processors for a while now... what are you saying?
which ones the only DDR3 models out are the X3 710/720 and X4 810
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#4
swaaye
DaedalusHelios said:
I have had many Gigabyte boards based on the P35-DS3R:

EP35C-DS3R x2
P35C-DS3R x2
P35-DS3R
EP35-DS3R

None of those needed any extra volts at MCH and they have mild OC's. I still have two in my house. Thats the most of the same series I have ever had. Funny thing you use that as an example being one of the best OC'ers of their time for the money. A few of those had 64bit Vista and 8GB of RAM like the one I gave to my GF. It had no issues that I have seen. :wtf:

I think your issue is the RAM you used. Its probably not on the Supported memory list. Common mistake really.
Just do some searches for P35 and 8GB. See what you find. :)

It definitely comes down to a combination of board and RAM quality. I have 4 sets of 2x2GB. Some of them will work in my P35 at 8GB just fine. It dramatically affects overclockability however. A friend of mine with an Abit IP35 couldn't get 8GB going no matter what with expensive OCZ Reaper 2x2 800 kits. I do believe that it's very important to get 1.8v RAM instead of stuff that has had its capabilities stretched with more voltage.

As for my DFI nF4 Ultra-D problem, well that was more of a board problem I think. The old DFI street forums were quick to tell you that running 4 DIMMs was a feat. Although I don't really have a feeling for how problematic S939 was in general for this.
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