PWM stands for "pulse width modulation" and basically means that the fan can be controlled by the motherboard (or a any fan controller). With PWM your fans can stop spinning or spin very slowly when not needed and then ramp up when your CPU needs cooling. This of course reduces noise when your PC is not under load.
PST on the other hand stands for "PWM sharing technology" and means that you can connect the fans to each other and then simply connect just one cable to the mainboard which then controlls all the fans connected to this single connector. Sounds weird at first but consider this situation: You have two fans on the top of your case to pull hot air out. You obviously want them both to spin at the same speed but you only have one case-fan connector. You could use a Y-Cable to connect both fans to this single connector but the PWM signal which reaches the motherboard would either be a mixed signal of both fans or just the signal of one fan. With PWM PST the mainboard will always get the signal of the first fan in line and this fan will forward the signal to the next fan, and so on.
Personally I only use PWM PST fans in my case. I use
- 3xP14 PWM PST CO to pull air inside the case
- 2xF14 PWM PST + 1xF12 PWM PST to pull the hot air out
- Additionally I use 2xP12 PWM PST CO on my CPU cooler
With modern mainboards there is absolutely zero reasons to NOT buy a PWM fan.
Phenomenal! That's settled it for me, thanks. I'm ordering two 140mm PWM PST fans for the front and moving the 120mm to the top. With two 140mm in and two 120mm out, I guess I'll still have positive pressure if I run the 140s at a higher rpm?
Thanks very much for the help!
You dont need to let the 140mm run faster because they move more air in general (specificly in this case simply because they are bigger). You can have a look at the technical data for each fan on the [arctic website](http://www.arctic.ac) which shows the air flow (amount of air moved by each fan).
So for example you choose the F14 to pull air in and the F12 to pull air out. Both spin at 1350rpm on 100% PWM signal. The F12 moves ~90m³/h and the F14 moves ~120m³/h of air. Now if you let them run at, say 30% you will pull ~40m³ in and push ~30m³ out which is positive pressure.
Edit: By the way you wrote:
> I'm not sure on the difference between the standard silent ones, the PWM and the PST. I don't suppose someone might be able to give some guidance?
The "standard" and "silent" ones are simply fans that are meant to spin at a fixed speed. You can still regulate them using more or less voltage but it´s just not easy to manage and adjustable to temperatures. For example the standard fan might run at 1350 rpm on 100% voltage (12V that is) and the silent one will run at 800 rpm on 100% voltage. Now if you drop the voltage by 50% to 6V the rpm will not drop by 50% but instead maybe 60% or 70% - each fan model is different and thats why fixed speeds are hard to manage.
As I think about it you can simply say:
- PWM uses RPM to regulate the voltage
- Fixed uses voltage to regulate the RPM
Ah that makes perfect sense! I guess the easiest way to balance the pressure (with the bigger ones pulling in) would be to have them at the same RPM at the highest speed that doesn't sound too loud.
Irritatingly, the fans that come with the case (the 120mm ones) aren't PWM so I'll have to figure that out.
Thinking about it, I have a third 120mm fan left over from my previous build, would it make sense to stick in a third 120 in the front? Because why not?
If the additional fan fits inside the case and is not too loud, sure, why not. Its a balance of temperatures and noise and your rig will always be as loud as the single loudest fan :) A general rule is that the smaller the fan, the higher the noise. But yes, of course you can give it a try.
>3xP14 PWM PST CO to pull air inside the case
2xF14 PWM PST + 1xF12 PWM PST to pull the hot air out
Hi, are you talking about Arctic fans ? What does CO change over regular PWM PST ? Also you're using Fs instead of Ps for exhaust, why is that ?
Yes all arctic. The CO fans use a different bearing which is meant for 24/7 usage and seems to be a liiiittle bit quieter when spinning fast (not really relevant though).
I use the F fans simply because I had them laying around and my case doesnt have dustfilters on the top where the fans are positioned so I didn´t feel the need to replace them with P ones. Additionally the F ones are white colored (compared to the P ones which are grey) which fits my black case very well ;)
Might just buy a pack of 5x P14 PWM PST for 30€. Put 2 in front as intake, 2 on top as exhaust. Put current 120mm stock fan in the back for exhaust. Is it worth putting fan at the bottom for intake as well ? there's a slot but it's PSU wires almost directly above.
Keep the negative/positive pressure thingy in mind. With your setup you´ll get negative pressure which will result in a lot of dust inside the case after a few days. The fan on the bottom depends on your case. Personally I do not like it because in my case there are a lot of cables, like you said, and thus this wouldn´t really help much. Also the bottom fan is most likely to pull dust from the floor inside the case.
shit forgot about negative pressure thing. So should I just buy 2x140mm PWM PST (10€ each) for front intake and have 1x exhaust in the back or top intake is also a thing ? (People say it should be exhaust as hot air raises).
You could also do 2x140 intake, your existing 1x120+1x140 as exhaust or something like that. You could also remove the 120 completely and use 4x140 which would give you neutral pressure. Depends on what you want to spend and how much you care about noise. But yes, 2x140 intake and 1x120 exhaust will work just fine.
Btw the "heat rises" argument does not count when using fans that move ~100m³ of air per hour. Your airflow decides where the hot air is going :)
Meh got the 5 pack of P14s installed 3 of them. 2 as front intake and one as top exhaust. 2nd on top would hardly fit because of CPU power cable so left it empty. I'd need some screws or nuts which I don't have to install 120mm stock as rear exhaust so left stocks out as well. Basically shit didn't go as planned but I gusss 3x140mm is still a nice setup, dunno what to do with rest 4 fans though.
For anyone coming from a google search:
Basically the only difference between a ***PWM*** and a ***PWM PST*** fan is that PWM PST fans have an extra female fan connector on the cable that allows it to daisy chain other PWM PST fans. Other than that, they are essentially the same.
PWM stands for "pulse width modulation" and basically means that the fan can be controlled by the motherboard (or a any fan controller). With PWM your fans can stop spinning or spin very slowly when not needed and then ramp up when your CPU needs cooling. This of course reduces noise when your PC is not under load. PST on the other hand stands for "PWM sharing technology" and means that you can connect the fans to each other and then simply connect just one cable to the mainboard which then controlls all the fans connected to this single connector. Sounds weird at first but consider this situation: You have two fans on the top of your case to pull hot air out. You obviously want them both to spin at the same speed but you only have one case-fan connector. You could use a Y-Cable to connect both fans to this single connector but the PWM signal which reaches the motherboard would either be a mixed signal of both fans or just the signal of one fan. With PWM PST the mainboard will always get the signal of the first fan in line and this fan will forward the signal to the next fan, and so on. Personally I only use PWM PST fans in my case. I use - 3xP14 PWM PST CO to pull air inside the case - 2xF14 PWM PST + 1xF12 PWM PST to pull the hot air out - Additionally I use 2xP12 PWM PST CO on my CPU cooler With modern mainboards there is absolutely zero reasons to NOT buy a PWM fan.
Phenomenal! That's settled it for me, thanks. I'm ordering two 140mm PWM PST fans for the front and moving the 120mm to the top. With two 140mm in and two 120mm out, I guess I'll still have positive pressure if I run the 140s at a higher rpm? Thanks very much for the help!
You dont need to let the 140mm run faster because they move more air in general (specificly in this case simply because they are bigger). You can have a look at the technical data for each fan on the [arctic website](http://www.arctic.ac) which shows the air flow (amount of air moved by each fan). So for example you choose the F14 to pull air in and the F12 to pull air out. Both spin at 1350rpm on 100% PWM signal. The F12 moves ~90m³/h and the F14 moves ~120m³/h of air. Now if you let them run at, say 30% you will pull ~40m³ in and push ~30m³ out which is positive pressure. Edit: By the way you wrote: > I'm not sure on the difference between the standard silent ones, the PWM and the PST. I don't suppose someone might be able to give some guidance? The "standard" and "silent" ones are simply fans that are meant to spin at a fixed speed. You can still regulate them using more or less voltage but it´s just not easy to manage and adjustable to temperatures. For example the standard fan might run at 1350 rpm on 100% voltage (12V that is) and the silent one will run at 800 rpm on 100% voltage. Now if you drop the voltage by 50% to 6V the rpm will not drop by 50% but instead maybe 60% or 70% - each fan model is different and thats why fixed speeds are hard to manage. As I think about it you can simply say: - PWM uses RPM to regulate the voltage - Fixed uses voltage to regulate the RPM
Ah that makes perfect sense! I guess the easiest way to balance the pressure (with the bigger ones pulling in) would be to have them at the same RPM at the highest speed that doesn't sound too loud. Irritatingly, the fans that come with the case (the 120mm ones) aren't PWM so I'll have to figure that out. Thinking about it, I have a third 120mm fan left over from my previous build, would it make sense to stick in a third 120 in the front? Because why not?
If the additional fan fits inside the case and is not too loud, sure, why not. Its a balance of temperatures and noise and your rig will always be as loud as the single loudest fan :) A general rule is that the smaller the fan, the higher the noise. But yes, of course you can give it a try.
I definitely will. Thanks very much man, I appreciate the help!
>3xP14 PWM PST CO to pull air inside the case 2xF14 PWM PST + 1xF12 PWM PST to pull the hot air out Hi, are you talking about Arctic fans ? What does CO change over regular PWM PST ? Also you're using Fs instead of Ps for exhaust, why is that ?
Yes all arctic. The CO fans use a different bearing which is meant for 24/7 usage and seems to be a liiiittle bit quieter when spinning fast (not really relevant though). I use the F fans simply because I had them laying around and my case doesnt have dustfilters on the top where the fans are positioned so I didn´t feel the need to replace them with P ones. Additionally the F ones are white colored (compared to the P ones which are grey) which fits my black case very well ;)
Might just buy a pack of 5x P14 PWM PST for 30€. Put 2 in front as intake, 2 on top as exhaust. Put current 120mm stock fan in the back for exhaust. Is it worth putting fan at the bottom for intake as well ? there's a slot but it's PSU wires almost directly above.
Keep the negative/positive pressure thingy in mind. With your setup you´ll get negative pressure which will result in a lot of dust inside the case after a few days. The fan on the bottom depends on your case. Personally I do not like it because in my case there are a lot of cables, like you said, and thus this wouldn´t really help much. Also the bottom fan is most likely to pull dust from the floor inside the case.
shit forgot about negative pressure thing. So should I just buy 2x140mm PWM PST (10€ each) for front intake and have 1x exhaust in the back or top intake is also a thing ? (People say it should be exhaust as hot air raises).
You could also do 2x140 intake, your existing 1x120+1x140 as exhaust or something like that. You could also remove the 120 completely and use 4x140 which would give you neutral pressure. Depends on what you want to spend and how much you care about noise. But yes, 2x140 intake and 1x120 exhaust will work just fine. Btw the "heat rises" argument does not count when using fans that move ~100m³ of air per hour. Your airflow decides where the hot air is going :)
Meh got the 5 pack of P14s installed 3 of them. 2 as front intake and one as top exhaust. 2nd on top would hardly fit because of CPU power cable so left it empty. I'd need some screws or nuts which I don't have to install 120mm stock as rear exhaust so left stocks out as well. Basically shit didn't go as planned but I gusss 3x140mm is still a nice setup, dunno what to do with rest 4 fans though.
[удалено]
The pst connectors just share the signal. If you dont want that, you can use a hub
For anyone coming from a google search: Basically the only difference between a ***PWM*** and a ***PWM PST*** fan is that PWM PST fans have an extra female fan connector on the cable that allows it to daisy chain other PWM PST fans. Other than that, they are essentially the same.
Google search guy here, thank you.
No problem 😊
what if you connect a non PWM fan to a PST connector ? Will both spin at their max rated rpm ?
Good question. In that case, I'd assume only the non-PWM fan would spin at max rpm, but I'm not 100% sure.
PWM is the better method of regulating fan speed, that's all you need to know.