Possible to run 3 200mm fans off mobo fan headers?

[kypron77]

Hi, I have an Asus P6X58D-E, and wanted to run 3 200mm Coolermaster 700 rpm case fans off of the motherboard chassis fan headers. Just concerned that on startup the board might pull too much current or something, as they are very large fans. Anyone else running multiple large fans off their mobo fan headers? (My cpu fan as well runs of the cpu fan header)

 

[mfenn]

Take a look at your mobo manual and find the current rating of the headers. Then look at the fans and find their current ratings (should be on the sticker on the hub). If the mobo rating is less than the combined fan ratings, then no. Otherwise, yes.

 

[BTRY B 529th FA BN]

I wouldn't tax this headers too hard if you are borederline on the specs.. never know how it's going to act.

 

[DesiPower]

If its fixed RPM then why the heck bother?

 

[dave_the_nerd]

mfenn is absolutely right.

As I am lazy and don't like doing research, I would play it safe and plug them into the PSU. Not worth messing with, especially if you're OCing.

 

[mfenn]

If its fixed RPM then why the heck bother?

Good point!

 

[BoomerD]

If its fixed RPM then why the heck bother?

Motherboards can control the speed of non-PWM fans...

 

[DesiPower]

I wonder if a mother board can increase the speed of a fan to more than its rated RPM, in this case 700. If not why would you want to reduce the speed to less than 700 RPM, the sound level is rated at 19 dBA, its not loud at all, what would you gain at below 700 RPM... except for a NOISELESS PC

 

[kypron77]

So the three fans are rated at .28 amps apiece. All three are currently hooked up to my mobo fan headers, and the bios controls them to run at 500 rpm normally, and when cpu gets up to about 60c they go up to 650 rpm. They are really quiet at 500 rpm.

I couldn't get official limits on the fan headers, I only know the cpu header takes a 2 amp fan. I'm assuming that .28 amps per header should be fine, but would startup from cold boot of a 200mm fan have much higher amperage requirements than that of a smaller fan? I'm just figuring the increased blade size would offer increased resistance on start up.

 

[mfenn]

.28A is very low, you should be fine. Any brief amount of inrush current over the rating shouldn't be a problem (if it were, you would have blown things out the first time).

 

[kypron77]

Ok thanks, I feel safe enough to leave it hooked up this way - at least until I buy a quieter case again. Currently using a HAF 922 with additional 200mm side fan, and trying to get it as quiet as possible. The S-Flex 1600 rpm fan I have on my Hyper 212 Plus is the loudest part about it.