AC 120 PWM not working with AC Freezer 7 Pro

[lp231]

I recently bought 4 AC 120 PWM case fans to replace the CM fans that came with my case.
I daisy chain the case fans, plug it to the 4-pin CPU header, and plug my CPU to the end of the daisy chain.
I turn on my system, head into bios and found out my CPU is running at a max 3000rpm!
But when I reconnect my AC Freezer 7 Pro directly into the 4-pin CPU header, PWM kicks in and runs the fan at a quiet 1036RPM.

Does any one have the same type of setup or is the AC 7 Freezer Pro (rev 1.1) not compatible with AC 120 PWM?
Please help!

fans I just bought
http://www.newegg.com/Product/Product.aspx?Item=N82E16835186033

 

[blade061188]

Hmm, the specs say the max RPM on the fans you bought is 1350RPM. Could be that your BIOS is getting an incorrect reading.

You should also try just using one off of the 4 Pin CPU connector to see how it controls. I don't know for sure if daisychaining the fans have an effect on the fan speed, but for testing, isolation is always better!

 

[lp231]

The board I have is a Asus Rampage Formula (s775), unfortunately it only has 1x 4-pin connector, rest are just 3-pins.
The 3000RPM the bios reads is coming from my CPU HSF, which somehow PWM don't work when I plug to a daisy chain. When the CPU is by itself, PWM works fine.
I'll try your suggestion, once I get a chance (currently not at the machine).

 

[blade061188]

Sure. Let me know how it goes.

 

[lp231]

Here is a update

I connect my the case fans individually to the 4-pin and PWM works. On silent it runs around 750RPM give or take.
I daisy chain my case fan and PWM works too, fans are silent.
When I finally connect my AC 7 Freeezer Pro to the daisy chain, PWM function is broken and all fans runs a max speed. Disconnect AC 7 Freezer Pro from daisy chan and PWM kicks back in.

Maybe AC 7 Freezer Pro (rev 1.1) is not compatible with their AC 120 PWM?

 

[blade061188]

Hmm, well I looked up this specification:
http://www.formfactors.org/developer%5Cspecs%5CREV1_2_Public.pdf

It looks like v1.1 is pretty old, but I don't think that should stop it form working. Are all 4 wires connected to the motherboard? I see a couple different connectors coming off the fan in the product photos on newegg.

Page 17 in that spec sheet shows 4 pins, ground, power, sense and control, they all need to be getting a signal to control the fan I believe

 

[lp231]

All 4 wires are connected to the board. The fan has a 4 pin plug + 4 pin header (to allow daisy chain). And a 3 pin to sense fan speed. Plugging the 3 pin or not makes no difference since the yellow wire is repeated in the 4 pin connector.
It seems another reviewer has the same problem and no solutions?

For now, looks like my CPU cooler ain't going to work with those case fans so I connected my CPU cooler directly to the 4-pin.
Still have my case fans daisy chain, but converted one of them to a 3-pin and all fans speed are running on silent without PWM.
I may get it to work either by getting a 4-pin PWM splitter, change the CPU cooler, or wait until upgrading the entire system and have a board with extra 4-pin connectors.

Thanks for your help!

 

[lp231]

Best answer selected by lp231.