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Only detects 2 out of 3 sys fans and the cpu fan

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April 29, 2011 6:36:37 PM

Only 1 sys fan and the cpu fan actually works correctly with the proper RPM... sys fan 2 is only running at 800-900RPM and in bios and overclocking center(the program that came with my motherboard)says that there is no 3rd fan even plugged in... All 3 fans work but I can tell that 2 of them are running slower...

I wouldnt be very worried about it because my CPU temp is only 21C and sys is 36C but my IOH.. not even sure what that is, memory maybe? Is idle at 70-74C and pushes 80C when gaming so I want all my fans working properly to see if that will help much
a b B Homebuilt system
a b à CPUs
April 29, 2011 7:58:58 PM

IOH = Input/Output Hub. 74 C isn't bad; in fact, that's normal. If you live in a warmer climate area, you may want to consider upgrading your case fans, like using 120 mm, instead of the 80 mm.
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April 29, 2011 8:46:10 PM

Im using 2 230mm and 1 140mm I have another 230mm fan but motherboard only has 3 sysfan slots so im getting a Y split to run 2 fans on one...

My main question really is why is the fan running at half the RPM it should be and the 3rd fan even though it IS running it doesnt recognize a 3rd fan even being there.. Whenever I get on I get a warning saying that my system fan 2 is under minimum RPM

Ah okay.. well thats just idle when im gaming itll get to 82C... that probably isnt too terrible either really.. I just want my fans working properly
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May 5, 2011 7:36:11 AM

Ah I was reading up on the MSI Pro-E motherboards and read that the thermal paste they use is cheapo... So I took off the heatsink replaced theirs with arctic silver5 and temp went down to 62C ^_^ I feel more comfortable with that, because it used to get up to mid 80's on hot days I would be nervous on days 100+ in summer

Got that Ysplitter for fans so I could have all running.. I have 3 230mm fans and 1 140mm now they all run but still shows low rpm on 2 of them, is it just because their 230mm and so their rpm is lower or should that even matter? Idk
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a b B Homebuilt system
a b à CPUs
May 6, 2011 8:02:31 PM

The Y cable is responsible for sending electricity to the fans, but doesn't regulated the voltage supplied, so, although they all work, they're not all necessarily getting the same voltage. This would explain why the RPMs are lower on the two fans.

The size of the fan is significant to the volume of air being pushed/pulled. The bigger the fan diameter, the bigger the volume of air. The RPMs are, of course, relative to voltage-more voltage equals faster revolutions.

If you want to get technical about it, though, from a pure physics point of view, a bigger fan will have more drag. Of course then, the drag versus rotation equation would result with slower movement, but this isn't relative, since the concern here is measuring RPM, and not the actual speed of each revolution. In short, yes, a 140 MM fan could theoritcally be able to reach X RPM sooner than the 230 MM fan, but this goes beyond the scope of this thread, forum, and quite possibly even beyond the manufacturer's intent.
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