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Intel 965G board...PWM gives fans VERY slow RPM's...

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  • Intel
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September 29, 2006 3:47:14 AM

Hi, my first post here as I have a few issues and this seems like a good place to get some good feedback.
This is one issue.

You know these PWM controlled fans, right? Well, the auto fan speed control I thought was a good idea, but I'm not liking it at all.

I was using 2 of the 3 or 4 fan plugs on the board, which are all PWM. The two I used were the cpu fan one and the chassis outlet fan (rear fan).

Problem is...low rpm's. Very low.
I was actually getting decent temps with my stock intel hsf. The fan was running a little on the slow side, but it didn't speed up much under full load like I thought it would.
Also, I was and did replace the entire HSF with a coolermaster hyper L3. Looked like it would do a good job for the price.

Anyhow, my stock intel cpu fan was running at a little over 1,000 rpm's. According to my desktop utility, this wasn't very fast. But I didn't pay much attention since temps weren't too bad, at least under idle.

But then I installed my hyper L3. Has a 92mm fan rather than the 80mm stock fan.

I installed it, and used ceramique as opposed to the wax/grease that was pre-applied.
But my temps weren't any better, in fact they were worse. So I fiddled with it a little and everything seemed fine.

Then I checked my rpm's. According to the specs of the fan, the fan should be running anywhere from 1100 to 2800 rpm's. It apparently isn't supposed to go under 1100, and it did have the 4 pin PWM compatible design, just like the stock intel, and I used the same plug as the stock fan, obviously.

But my rpm's weren't even close to 1100. They didn't even quite reach 600 rpm's at any point. At idle, I was getting maybe 550 rpm's. Then under full load, where the temp went up as much as 20c, the fan only increased to about 600 rpm's!
WTF is that all about?
Temp goes up 20c with the cpu nearing the red zone on the guage at a bit over 60c, yet my rpm's only go up by 50 from the measly 550 rpm's to start with?

Same with the 120mm rear fan. According to the guage, this was running around 600 to 700 rpm's under idle and full load. And I could barely feel any air pusing out the back. It's so slow that I can barely feel air coming out the back at all.
So I'm sitting here with my cpu above 60c and cpu usage nearing 100 while running some programs, and the best both my fans can do is like 600 and 700 rpm's?
Now, I don't know what the max rpm's of the coolermaster 120mm fan should be, it came with the case as did the front fan (which I have on full blast as its just a little 80mm fan and I love that intake!).
However, I know the max rpm's of that 120mm fan have got to be way above 700 rpm's.

So what is the deal here? The intel stock fan was at least running over 1,000 rpm's. Better than what I'm getting now, but that sure wasn't optimal either.
And for the record, my fans are fine. When I plug them directly into my power supply adapters (both the cpu and rear) they go on full blast. The difference is huge!

At this moment, I think I'm going to keep the cpu fan on full blast as it still isn't that loud and it keeps my cpu and mobo temps way down.
When in the PWM mode, my idle temp actually got up to around 58c! When in full blast, my idle temp right this moment is 36c!
Wow! What a difference.
I did, btw, end up using AS5 and took off the ceramique, but not much difference there. And the AS5 is only an hour old and my temps should drop a little more when it sets.

So I think I can safely say that my HSF is just fine. With the fan at its peak, my cpu temp (for a 3.4ghz Pentium D 945) being at 36c without the AS5 worn in yet is quite an achievement, I would think.
For now, I left the rear fan in the PWM mode at 600-ish rpm's. Not sure if that is bad or not for it to run so slow, but I also have my psu with dual fans taking in air at the top and pusing it out the back.
And with that back fan at higher rpm's, it really wouldn't make much if any temp difference, so I'll leave it slow and quiet for now, especially since my cpu fan is going full blast.

In summary then, I'm actually in pretty good shape right now.
However, is something wrong with my PWM modes? I even went into the bios and maxed out the settings as much as I could. Not much difference. Is it normal to get fan rpm's barely over 500 (cpu and/or rear) even when your cpu is under full load and burning up at over 60c?
Is there some way to use this PWM feature, but modify it to make the fans go faster (much faster) under idle and full load? I mean, if my temps and cpu usage are maxed out, you would think the fans should be kicked into high gear.
I mean, these fans were made to go a certain speed, so you would think PWM mode would at least push them near their max when the conditions are right. Yet they don't even come close.

Not sure what the problem is. Like I said, when plugged into the psu adapters, these fans really go. And I tried two different HSF's, neither of which gained high rpm's, and I also have the same issue with the rear fan. So where could the problem lie?
Or is this normal?

More about : intel 965g board pwm fans slow rpm

September 30, 2006 6:17:10 AM

Who makes your G965 board? If it is an Intel board they have made their fan speed control aggressively weighted towards higher thermals but lower accustics. I don't know what other board manufacturers have been doing with their thermal management controls.

Sorry
September 30, 2006 4:48:45 PM

Damn, thought I mentioned it was from Intel, but I guess I didn't.

I guess what is confusing is that the stock HSF was running over 1,000 all the time, regardless of temp.
If my temp was 40c it might be 1,050 rpm's. If my temp was burning up at 60c, it might only gu up 50 more rpm's.
Thanks for the thermal management Intel!

What was confusing was when I plugged the new HSF into the same plug the intel hsf was in, the rpm's were in the 500 range. And again, the temp, with such low rpm's, actually reached past 60c, yet the rpm's, if at all, might of went up by 50 rpm's, which obviously didn't help me out.
As I mentioned, this fan should be going up to 2,800 rpm's, not 500. And when I gave it a direct power source, this sucker really speed up and I have a cold running cpu, which is sweet, and its still dead quiet almost!
So this isn't a big issue, but I wonder who in their right mind would use this PWM mode to take care of their cpu temps?

And I explained above about how slow the rear chassis fan runs too (700-ish).

I was going to call intel, however....
I like Intel products, always have, never really had any major issues with them (this is the first, and its not that serious).
But when I checked their site to call them tech support, it said it would cost me like $25 just to talk to them once!!!
Apparently, this applies even if I just bought a product and have a question about it?
I don't know, but I just didn't bother. Maybe I misread something or there is another way I can contact them.
October 1, 2006 6:55:26 PM

Turn off the fan control from the motherboard and it'll run at max speed. Thats what I had to do with my setup. Of course I have a 120mm fan so it still only spins at 1200 rpm.
October 1, 2006 9:25:45 PM

Quote:
Turn off the fan control from the motherboard and it'll run at max speed. Thats what I had to do with my setup. Of course I have a 120mm fan so it still only spins at 1200 rpm.


Hmmm. I don't know how to turn off fan control. I've been through the bios and have been through the fan settings. I think there is some sort of sensitivity settings, but I didn't see off settings, I might have to check again, there was a few options that weren't clear as to what they do.

But would it matter if I plug these fans directly into the power supply connectors rather than turning off fan control and having them run at full speed that way? Or wouldn't it matter since they run full speed either way?
Or would one way be more power efficient?

It actually might be best if I could turn off fan control and plug my fans into the mobo. Even if the only benefit for me is to have a little less clutter with the psu wires.
!