Re: PC speaker

From: Kyle Moffett
Date: Thu Jun 14 2007 - 20:37:09 EST

On Jun 13, 2007, at 15:53:30, Pavel Machek wrote:
Other great examples are hardware that allows you to control voltages, fan speeds, and operating frequencies. Sometimes you can overvoltage it directly and blow it immediately. Other times, you can increase the voltage and operating frequency and decrease the fan speed to the point where it stops spinning. This is possible on many modern graphics cards and CPUs.

Not true for cpus; try it before spreading FUD. Thermal protection will kill the machine when cpu goes over 95C or so.

Well, sorta. Things tend to die early heat deaths if you repeatedly spike the temperature (different rates of thermal expansion and all that jazz). If you alternated repeatedly between max-CPU/no-fan and no-CPU/max-fan, staying just within the thermal kill limits and spending 3/4 of the time at near max temp, you'd probably have a 30% chance to kill an average CPU within a couple weeks.

I know when designing the G5 CPU, IBM had to be _really_ careful about the variably high operating temperature. Their first few designs ended up having BGA breakdown well before the desired lifetime due to thermal creep (long-duration at high temp) and fatigue shear failure (alternation between high and low temp). There's a paper somewhere on the web about the whole deal.

Kyle Moffett

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