AMD processor overheating protection on Asus motherboards

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

In article <s0luh1t4pj1cale28evojhmeel1qvl7ke0@4ax.com>, Hans-Georg Michna
<hans-georgNoEmailPlease@michna.com> wrote:

> Do modern motherboards like the A8N-SLI protect AMD processors
> (Athlon etc.) from overheating? For example when the fan fails?
>
> I'm not talking about the warning systems like Asus Probe, or
> the temperature regulation systems. I'm talking only about the
> case that all those systems fail and the processor reaches
> temperatures beyond 85 or 90°C.
>
> Comparable Pentium processors have overheating protection built
> in, so it would be nice if at least the motherboards would
> provide similar protection for AMD processors.
>
> I just built a few computers using the fine A8N-SLI Premium
> motherboard and am quite happy with them so far, particularly
> after finding the BIOS setting to regulate the processor fan
> speed and thus enjoying the almost perfect silence.
>
> Of course I read the manual. It doesn't say anything clear about
> this question. This would indicate that there is no protection,
> because it would be very stupid for Asus to do good things and
> not talk about them. (:-)
>
> Hans-Georg

Here is section 3.7, from AMD Athlon64 S939 datasheet doc #31411.
The same description exists for S754 processors as well (#31410).

"3.7 THERMTRIP_L

The processor provides a hardware-enforced thermal protection
mechanism. When the processor¹s die temperature exceeds a
specified temperature, the processor is designed to stop its
internal clocks and assert the THERMTRIP_L output.

THERMTRIP_L assertion is only valid when PWROK is asserted and
RESET_L is deasserted. THERMTRIP_L assertion indicates the
processor die temperature has exceeded normal operating
parameters. PWROK must be deasserted in response to a THERMTRIP_L
assertion to enable proper processor operation.

Once asserted THERMTRIP_L remains asserted until RESET_L is
asserted. If the processor¹s die temperature still exceeds the
thermal trip point when RESET_L is deasserted, THERMTRIP_L will
immediately be reasserted and the processor¹s internal clocks
stop."

So, that means the processor has some protection, but it is not
stated as to exactly what the trip point is for overtemperature.
This kind of thermal protection is generally not user programmable,
as engineers set the temperature according to damage criterion.
On Intel, this is 135C, so for AMD it should be pretty hot too.

This mechanism is meant to protect against a cooling failure,
and is not a way to establish a long term operating temperature.
They don't want you to run the processor at 134C all the time :-)

On the previous generation of Asus AMD boards, they used a separate
chip to do the thermal protection function. There might be an
Attansic chip that does something like this as well. These devices
monitor the voltage across the thermal diode on the processor
die.

http://www.winbond-usa.com/product [...] 85TS-S.pdf

There were some early Athlon boards that have no protection.
Those are the ones you have to be careful with.

HTH,
Paul

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

On Thu, 08 Sep 2005 00:29:43 GMT, nospam@needed.com (Paul)
wrote:

>Here is section 3.7, from AMD Athlon64 S939 datasheet doc #31411.
>The same description exists for S754 processors as well (#31410).
>
> "3.7 THERMTRIP_L
>
> The processor provides a hardware-enforced thermal protection
> mechanism. When the processor¹s die temperature exceeds a
> specified temperature, the processor is designed to stop its
> internal clocks and assert the THERMTRIP_L output.
>[...]

Paul, Robert, Homer,

thanks a lot for your excellent information! Seems I was too
suspicious. (:-)

Computers are running fine (after finding a workaround for an
nForce-Maxtor incompatibility).

Hans-Georg

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