Case fan from 12v to 5v

zapian_

Weaksauce
Joined
Oct 25, 2004
Messages
99
Well its pretty obvious switching to 5v will make your loud fan dead quiet but any downside doing this, besides lower RPM and CFM?

Do you just change the wiring connection on the molex from the fan and PSU?
 

RawsonDR

Gawd
Joined
Aug 18, 2004
Messages
583
The change from 12 to 5 would be dramatic, as well. Seems almost not worth it. You could also look into the 7v mod,
 

_G_

[H]ard|Gawd
Joined
Dec 25, 2002
Messages
1,378
works well on ultrahigh cfm/noise (tornado) fans but some case fans may not even
start@5v
 

Spidey329

[H]F Junkie
Joined
Dec 15, 2003
Messages
8,683
_G_ said:
works well on ultrahigh cfm/noise (tornado) fans but some case fans may not even
start@5v

I use it on my Tornado 92mm fan with a toggle switch. It's like night and day. But, there's also a 8 degree difference in temperatures with it off (8 degrees higher) according to my case sensor which is on my harddrive and not near the fan.
 
Joined
Oct 2, 2003
Messages
2,173
Unless your using 120mm case fans, I think 7-volting your case fans would offer the best noise/performance ratio.
 

Dark Ember

[H]ard|Gawd
Joined
Jul 30, 2001
Messages
2,021
Yeah, like G said, some fans may not be able to spin up at 5V. None of the ones I use can. If you want to undervolt them, it seems that 7V is pretty good from a performance/noise perspective. Decreases noise dramatically, and still will move a lot more air than it would at 5V.

Just my $.02
 

zapian_

Weaksauce
Joined
Oct 25, 2004
Messages
99
Thanks for the replies. I've researched switching to 7v as you guys mentioned and its the way to go with 120mm.
 

Pixeleet

[H]ard|Gawd
Joined
Feb 24, 2003
Messages
1,145
Totaly noob question coming up, so I have the flame shield ready :)

How do you undervolt a fan to 7v? :(
 
Joined
Oct 2, 2003
Messages
2,173
Pixeleet said:
Totaly noob question coming up, so I have the flame shield ready :)

How do you undervolt a fan to 7v? :(

It is in the FAQ under case modding. Basically intead of using a 12V line and ground (yellow and black, respectively), you use 12V and 5V (yellow and red, respectively) to create a potential difference of 12V-5V, or 7V.
 
Top