AMD processor overheating protection on Asus motherboards

  • Thread starter Thread starter Hans-Georg Michna
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Hans-Georg Michna

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
 
Just because ASUS doesn't say anything about it doesn't mean it's not there.

Why would ASUS keep emphasizing a standard feature, ASUS C.O.P. (CPU
Overheating Protection), that has been available on their AMD CPU
motherboards since early 2002?

This feature doesn't help to differentiate their motherboards from their
competitors motherboards since all recent AMD CPU motherboards would have
this equivalent feature.

On the A8N-SLI Premium, which I currently have in my system, the Vocal POST
Reporter will even tell you "CPU temperature too high" if it detects CPU
overheating during POST. This would indicate that there is protection
present and that the CPU temperature is being monitored at all times. If
the CPU overheats the system will shut down.
 
Hans-Georg Michna said:
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
Click to expand...

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/products/winbond_products/pdfs/PCIC/W86L785TS-S.pdf

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

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

Huh! IE do not take the heatsink off forget about it and switch on (Athlon
1600). Bang. I should know. Laugh all you want.
 
Hans-Georg Michna said:
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
Click to expand...

I think that CPU overheating shutdown is pretty standard (or universal)
on Athlon 64 boards. AMD CPUs don't have the clock modulation feature
that Pentium 4s have which allows the CPU to function at a lower clock
speed, they just have the hard shutdown (THERMTRIP) as Intel's CPUs have
had for years.

Some older Athlon XP boards either had no protection at all, the
protection was dependent on software and hence could fail to function if
the CPU locked up, or the temperature sensing was based on a socket
thermistor and not the thermal diode in the CPU and hence would respond
too slowly to be able to shut down the CPU fast enough under conditions
such as the heatsink falling off. These problems should not exist on the
A64 boards however.
 
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.
[...]
Click to expand...

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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