Question about fan rpm max

[jack bauer]

I bought a Scythe F model 1600rpm, and installed it (very quiet and pushes a lot more air than my thermaltake 1400 fan I had in there stock). I cut out the front grill, so there is nothing in front of the fan. Behind the fan, is 1/3 of the bottom of my HD, there are also the sides of the HD holder. Fan maxs @ 1577, but usually hangs out around a bit lower. What's up with that? Where's my 1600? I even hear some people get 1620 on newegg? I think the fan is fine, but think they rate these things in open air, am I right?

 

[imported_redlotus]

I assume that you're correct about them being rated in open air, but I don't know for sure.

As for why you are getting slightly lower RPMs, it's probably one of three things: voltage variations from your PSU, pressure build-up in your case, or just plain old manufacturing variation. Frankly, you shouldn't be too worried about a ~25 RPM variation. Heck, even a sag that small could be caused by atmospheric pressure (i.e. blame it on the weather )

-red

 

[Pens1566]

The fan isn't getting 12V. If it's on a controller, those sometimes only deliver ~11.5V to the fans.

 

[jack bauer]

I have it hooked up to a seasonic s12 500w, and all the plugs seem to be in the right place. I'll take it out when I get the rest of my fans and see how it runs outside the case along with all my fans.

 

[RallyMaster]

jack bauer, honestly, you shouldn't be worrying. you've nitpicked way too many things that seriously don't matter. is it going to kill you to see a fan spin slightly slower than it is rated? please....my Freezer64 Pro spins at 2163 RPM from a rated 2200RPM. do I worry? NO! come on dude...use common sense, it's not going to be perfect all the time.

 

[Operandi]

All fans are rated +/- 5 - 10%, and speed is directly related to your 12v rail. So anyone getting over 1600RPM probably has a slightly high 12v rail. I wouldn't worry about it, 1600RPM out of a 120mm fan is way more then what is needed for an intake anyway.

 

[jack bauer]

Originally posted by: RallyMaster
jack bauer, honestly, you shouldn't be worrying. you've nitpicked way too many things that seriously don't matter. is it going to kill you to see a fan spin slightly slower than it is rated? please....my Freezer64 Pro spins at 2163 RPM from a rated 2200RPM. do I worry? NO! come on dude...use common sense, it's not going to be perfect all the time.

come on you guys, i said my fans are fine. just learning about how the fans function.

 

[pkme2]

1500RPM on 120mm fan keeps it quiet and maybe cheap. Move more air and raise the rpms leads to more noise.

 

[jack bauer]

Is it true it is best to have your intake fan a little faster than exhaust?