X2 Bug Warning: Thermal throttling bug / power saving mode use could fry your CPU!

[STEvil]

What Socket 939 motherboards have the most robustly designed
Vcore power regulators with the most number of "phases"?

I've heard about 3-phase, 4-phase, 5-phase, etc. power converters
for Vcore generation but I don't know what common motherboards
for X2 / FX-53 / FX-55 Socket 939 really have the best regulator capacity.
Anyone know? How about for S-939 AGP boards?

AGP boards -- Asus A8V deluxe vs. MSI Neo2 plat vs. NVidia NF3 Ultra D?


Every time I see a reference to someone "over-volting" something to
"increase overclock stability" I sort of grimace and laugh. As an EE I know
that "too many volts" usually just fries ICs, and doesn't really help them
work "better/faster" in most ways. I think the MAIN effect of
"increasing the volts" to demonstrably increase platform stability is really
just to provide greater CHARGE / ENERGY into the "too-small" power filter
capacitors so that when there's a large fast-rising load like a high MHz burst
of I/O or computation that there's a better chance there'll be enough energy
in the little filter capacitors to sustain at least the minimally necessary
current / voltage to keep the electronics working correctly until the relatively
slow (in comparison) voltage regulators can squirt out more energy / current
to recharge the voltage on the filter capacitors up to the proper level again.

Thus what's really needed isn't MORE voltage, it's BIGGER / BETTER / MORE
capacitors and voltage regulators to provide more current / energy more
frequently to the CPU / chips when those burts of power are needed. If
this was done one should be able to run at 100% nominal Vcore / Vdimm / etc
and have as much of a overclock with no risk of overclocking causing
transient undervolting as is possible limited by the actual speed of the ICs.

More Vcore regulator phases with higher quality and amperage FETs per
phase should help this.

Evidentally this kind of STPCLK transient causing power regulator
instabliliy has been true for some time:
http://unixmafia.port5.com/news/00211001.html

"Overheating problems on some KT133(A) Motherboards, namely Asus
Last update: 2002-12-05
...The problem
The BIOS on several via KT133 and KT133A motherboards disable the HLT , STPCLK and STPGNT instructions of the processor (apparantly, some A7M266 boards have it too). These states are responsable for power savings (and heat production) under the APM and ACPI specifications. The boards that have these disabled therefor do not completely implement those specifications, although they do claim so in their propaganda.
This can have several reasons, but one of the most common is to hide the fact that a particular board has an inferior power-supply. Which seems to be the case with my Asus.
Asus uses a 2-phase power supply with 4 capacitators onboard, while most boards have a 3-phase supply with 6 capacitators. Especially the STPCLK instruction, which calls the C2 Power Management state of the Athlon processor, puts a heavy burden on the power supply, because switching between the lowest and highest power consumption can occur several times a second. The disadvantage of the C2 state is that it can interfere in realtime applications like video and audio, because it takes the processor a fraction of time to come out of it. Asus hides behind 'choppy audio' as a reason to disable both C1 and C2. If this were valid, why not supply a BIOS option to turn it on or off? "

I suspect this is the way it is happening.

In theory adding more voltage until the described affect creates a highly logarithmic increase in need for voltage shows how much "power" your board is capable of handling.

For example:

A processor scales well with voltage on one board, but not as well with another.

This implies that the board is at fault, and if placing an X2 onto the weaker board you may pass the maximum the board can deliver at even default settings (assuming first tested CPU was a single core A64).

This problem isnt exactly new either. Older KT133/KT133a boards only supported up to a certain CPU due to the power draw higher models required. Even KT266/266A had this problem. Some which stopped at a certain point were just because the manufacturer was too lazy to update the BIOS microcode (board was fully capable of going beyond "max" suggested CPU) but many (Epox 8kta3+, Asus A7V133, MSI...) couldnt handle it, even some running recommended CPU's couldnt.


What i'm trying to point out is that this is not a new issue at all.. and its not being hyped at all if you remember past experiences.

EDIT

I should mention that I very much dislike temperature protection that is dependant on the BIOS.

If a small IC were used to monitor PWM/Choke/CPU temperatures (accurately) and connected to the power switch (or a secondary one) so it could power off the machine even if the CPU had failed and was locked up this would be a much better solution.

better yet if a temperature resistant co-processor were placed on the motherboard or CPU die that would function and maintain power loads (high power resistor may be required intermittantly) to reduce transients when the "master" processor(s) failed we wouldnt have this problem at all..


And why does asus always skimp on parts? If memory serves correctly they completely removed the vref circuitry from their GeForce 3 boards feeding 3.3v direct to the I/O of the memory chips (not VDDR which can be taken as high as 3.8v at times with voltage modifications)..