I haven't assembled PC in long time, by now I'd expect you can build passively cooled PC if you use PC just for some regular office job and surfing without gaming and resource heavy apps or we are still not there? Back in the days undervolting was for me for interesting than overclocking to make PC as quiet as possible.
More than you cared to know about PC fans
31–40 of 102 posts
Re: More than you cared to know about PC fans
#32What a coincidence, 4x of the 120mm Noctua Redux fans just arrived this morning and are sitting on my living room table waiting to go into my rig. I love in-depth analysis of stuff like this. How do y'all like to manage (chassis) fan speeds? I have been out of the PC world for so long that I forget all pieces of hardware need to be managed.
FWIW I used to use software (Speedfan, and later something else I don't remember), but after upgrading to Noctua fans, I found whatever is built-in to the motherboard works just fine and gave up on the complication of software. I'm on my second system like this, and I've found they've both been a good temperature and nearly silent most of the time. Even maxed out, it still seems to be quieter and cooler than it would…
nice, that was what I was hoping to achieve
Re: More than you cared to know about PC fans
#33What a coincidence, 4x of the 120mm Noctua Redux fans just arrived this morning and are sitting on my living room table waiting to go into my rig. I love in-depth analysis of stuff like this. How do y'all like to manage (chassis) fan speeds? I have been out of the PC world for so long that I forget all pieces of hardware need to be managed.
I use a Corsair commander with a copy of system information viewer
Dig the fact that this thing comes with little temperature probes - my current case is probably a little too small for the setup I have right now and I am debugging the temperature zones / airflow. It's a Fractal Define C, i7-12700K, Radeon RX 6750XT OC. Initially my CPU cooler fans (2x) were pointed in opposite directions, lol. Would love a thermal camera, but these probes would probably be just as helpful.
Re: More than you cared to know about PC fans
#34> "there is no readily-available 24V source from an ATX power supply,"
This is false. ATX provides both +12V and -12V: * https://pinoutguide.com/Power/atxpower_pinout.shtml
Hooking them together would provide 24VDC. On a 350W PSU, I see -12V rated to supply 0.3A, which would allow for 24V fans drawing up to 7.2W of power, if desirable.
I don't see any reason to prefer 24V fans, however. The current losses over such short ranges are minimal, and I would think the larger economies of scale of 12V devices will keep 12V fans less expensive.
Re: More than you cared to know about PC fans
#35So looking forward to the incomplete "Form Factor" section!!!
Re: More than you cared to know about PC fans
#36How does a fan get power to drive the tach output, if the only power it gets is a pwm signal (which might be low when it needs to switch)?
Re: More than you cared to know about PC fans
#37How does a fan get power to drive the tach output, if the only power it gets is a pwm signal (which might be low when it needs to switch)?
Generally the fans are powered with a steady state DC source and the PWM is just logic signaling. If the fan is powered by a PWM source the tach output will not be a clean square wave (but could still be reconstructed, if the PWM frequency is sufficiently higher frequency than the fan's rotational speed).
Re: More than you cared to know about PC fans
#38Does anyone know if there are high-heat-resistant PC fans (and at what temperatures normal PC fans will melt)? The only fans I can find that claim to be heat-resistant are the Noctua Industrial PPC series which, aside from not being cheap at $33/piece are "only" heat-resistant up to 140C and the airflow isn't crazy high - subjectively the ones I've got feel like they move substantially less air than a standard diesel…
The DC brushless fans listed on Digi-Key max out at 100C; anything rated to 140C or high would be extremely specialized and costly.
Re: More than you cared to know about PC fans
#39I wish noctua would sell aftermarket replacement CPU fans for laptops. I thought there was something wrong with the loudness of my Dell laptop's fan (with low confidence), but I couldn't gauge that any replacement product wound actually be quieter or cared about noise levels.
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Re: More than you cared to know about PC fans
#40How does a fan get power to drive the tach output, if the only power it gets is a pwm signal (which might be low when it needs to switch)?
Generally the fans are powered with a steady state DC source and the PWM is just logic signaling. If the fan is powered by a PWM source the tach output will not be a clean square wave (but could still be reconstructed, if the PWM frequency is sufficiently higher frequency than the fan's rotational speed).
Well, PC fans come in 3-wire and 4-wire forms, where the 3-wire type has only pwm,tach and GND connections (no DC power).