whats a pwm?

Howard

Lifer
Oct 14, 1999
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It stands for Pulse Width Modulator/Modulation with respect to fan control (and some kinds of amplification, IIRC, but I digress). If you plug a fan into a PWM header, it'll drop the RPM by pulsing current (lower than 100% duty cycle) instead of dropping voltage.
 

TrevorRC

Senior member
Jan 8, 2006
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Originally posted by: HybridSquirrel
oh ok. i was wondering becuase in ITE it told me the pwm ic was 48C

Regulates the voltage going into your CPU [someone correct me if I'm wrong]... or something along those lines. Temperature is rather critical if you are using a dual core board, as it can get EXTREMELY hot [>70C]. Not quite boiling water, but getting close ;)

If it hits over 60, it is advised that you improve airflow in your case... it will be damaging your potential overclock... and anything that touches it might get toasty :] [As for the overclock bit, I was hitting a brick wall with this processor until I noticed how high the PWM IC temp was--put a fan over it, and voila. Wall gone.]


--Trevor

Edit:
Here you go:
Explanation about the PWM ICs/Effects on Overclocking
 

OSX

Senior member
Feb 9, 2006
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It's much better than normal volt regulation, because it's more efficient, and most motors will stop running after the volts get too low. It's better for your hardware.
 

HybridSquirrel

Diamond Member
Nov 20, 2005
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so is it good for it to be hot or keep it cool? because if i need to keep it cool i will switch the fan orientation again
 

Howard

Lifer
Oct 14, 1999
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Originally posted by: HybridSquirrel
so is it good for it to be hot or keep it cool? because if i need to keep it cool i will switch the fan orientation again
Electronics always perform better when cooler (not talking about ridiculous sub-zero temps here).
 

HybridSquirrel

Diamond Member
Nov 20, 2005
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hehe ok ill check temps again it was hitting like 50c which i guess isnt to bad is it? if i put a 120 in the front blowing in should i cool the pwm? i have an 80mm side fan but im using it to direct exhaust from the ac freezer 64 pro strait out of the case but when i was aiming it in the cpu was hotter but the pwm was cooler
 

GalvanizedYankee

Diamond Member
Oct 27, 2003
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Squirrel, if you want a very fine point on it, search the Cases & Cooling Forum in the archives for,"The MosFet Sink Mystery."

These small chips can generate considerable heat, particularly when one OCs. They can function very well at elevated heat levels, some FETs are speced to 125C. When things go wrong(very rare) the heat can get so high the solder melts. I've only seen pics.

The problem with cross flow heat sinks on the CPU as well as water cooling is mainboard air circulation takes a back seat. Sometimes the difference between a Ninja and SI-120 is that these chips*might* gain 20C in heat by using the Ninja. Is this bad...NO. As long as they stay under about 65C. Is having these chips cooler better...Yes, because board heat will move to the other electrolytics on the board through the traces to the capacitors. The caps are those tall cylinders that are next to the FETs and they service the FETs. Most caps are speced at 85C but the better ones are speced at 105C. So is there advantage to keeping the caps way below spec temperature, you betcha, because service life WILL be extended.

Thankfully, when caps fail, they generally fail in an open state. Like a circuit breaker. But when they fail in a closed state, all hell can break loose. That's when solder melts.

The area you are refering to is in a crowded space, between the CPU and i/o plate. This is a dead spot for air circulation and that is why your 64Pro has it's lower fins on the exhaust side curved down.

Your call what you do but I would go with what the HS manufacturer designed.

If you want to keep your current fan set-up, you could suspend a 60x10mm fan over this area, blowing down.


...Galvanized
 

HybridSquirrel

Diamond Member
Nov 20, 2005
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thanks galvanized i just figured id post up in here because it was already an ongoing thread. but im gonna do a search for the "the mosfet sink mystery" thanks ^_^

EDIT:i couldnt find it