X2 Thermal Throttling Bug

[Technonut]

I saw this posted Here @ Xtreme Systems Forums, and found it interesting... (Quoted from the original post):

There's a bug in the current revisions of X2 CPUs wherein either
the thermal safety throttling may be unexpectedly forced off, or wherein
its use could cause the CPU core voltage to spike, possibly frying the CPU.

If the thermal throttling is forced off e.g. in the BIOS as is suggested
as a "work-around" for this bug, it's possible that some BIOSs would permit
the CPU to continue to run continually even if it has reached temperatures
beyond which the CPU could be damaged; normally thermal
STPCLK speed throttling would reduce the CPU clock to prevent this
damage from being so likely.

If thermal throttling is NOT disabled as AMD suggests the BIOS does, *OR*
if user selected ACPI ower saving / utility functions triggers STPCLK
mode while the CPU clock is running at normal speeds, the voltage spikes
caused by the instantaneous 100 Watt <--> 0 Watt Vcore load change could
cause the system to spike or undervolt Vcore leading to either a crash
or very possibly a fried CPU!

Everyone should confirm with their BIOS vendor and settings for their
ACPI / thermal monitoring options in the BIOS that they're running the core
at safe temperatures and in a way that will not trigger STPCLK throttling /
power saving!

Here's the info from AMD:

http://www.amd.com/us-en/assets/content...e/white_papers_and_tech_docs/25759.pdf

Revision Guide for AMD Athlon? 64 and AMD Opteron? Processors 25759 3.51 06/16/05

124 STPCLK Throttling Causes Violation of VDD_ac Specification
on Some Dual-Core Processors

Description
STPCLK throttling during maximum power consumption operation generates large load steps and voltage transients that can violate the transient
voltage specification (VDD_ac). This problem is exposed on 4-layer
motherboards with single power and ground planes when the
core frequency is >2000 MHz.

Potential Effect on System
Violation of the VDD_ac specification leading to unpredictable operation.

Suggested Workaround
Do not enable STPCLK throttling on affected dual-core processors above 2000 MHz.

Fix Planned: Yes

 

[Duvie]

<Do not enable STPCLK throttling on affected dual-core processors above 2000 MHz.>

What is this cool-n-quiet??? I have always disabled that....

How do we know what boards would be effected by this??? Obviously a bios issue....partly a problem of using older existing hardware like the older sckt 939 mobos....

 

[Duvie]

i couldn't get link to work....

 

[fatty4ksu]

Bad news for AMD.

 

[Duvie]

I found a report that seem to suggest this is not an X2 thing but actually an E3 thing as well...it was in a different language but it seemed to be that was what it was referring to...

 

[Technonut]

Originally posted by: Duvie
Obviously a bios issue....partly a problem of using older existing hardware like the older sckt 939 mobos....

Before I even read the post @ Xtreme Systems, I read some posts here regarding high MOSFET temps using the X2, and figured there may be issues cropping up....

EDIT: I think the AMD PDF link works now....

 

[GuitarDaddy]

Originally posted by: Duvie
<Do not enable STPCLK throttling on affected dual-core processors above 2000 MHz.>

What is this cool-n-quiet??? I have always disabled that....

How do we know what boards would be effected by this??? Obviously a bios issue....partly a problem of using older existing hardware like the older sckt 939 mobos....

I don't think they are talking about Cool n Quiet, I think STPCLK controls the thermal shutdown point (shuts down the system when the CPU temp reaches an unsafe level). I think thermal throttling is code for shutdown.

If the workaround is disabling this feature, it wouldn't present a problem if you monitored your temps with a utility and set alarm levels well below the damage point. I never have let my temps get anywhere near the shutdown point on any of my CPU's anyway.

 

[theMan]

it sounds like a cool and quiet issue. good thing i dont use that... but im not planning on getting an X2 any time soon.

 

[jpeyton]

Yep, both myself and another user noticed the X2s stress the mosfets a little more than single cores, but we've been overclocking ours too.

I never enabled Quiet'N'Cool because I was overclocking, and I disabled Thermal Throttling as well, as soon as I booted up the X2 for the first time. Didn't even know about this issue when I did that, but I'm glad I did.

This seems to be an issue with the quality of your motherboard as well.