Extending Mobo PWM Function?

GSS

GSS

GSS

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My Asus P5N-D Mobo supports PWM on 3 of it's 4 fan headers and I use the Asus Utilities; AI Suite & PC Probe II to monitor these, also SpeedFan. System cooling is as follows;

1st = 4 pin CPU = CPU (OCZ Vendetta CPU Cooler fitted)
2nd = 3 pin Chassis Fan 1 = MB Chipset/System (Fractal Design 60mm Silent Series Cooling Fan fitted)
3rd = 3 pin Chassis Fan 2 = RAM (OCZ XTC Cooler fitted)
4th = 3 pin PWR (Not PWM) = (Akasa AK-FN057 Apache Super Silent 120mm Fan fitted - Rear Exhaust)

I want to extend this with one of these http://www.overclockers.co.uk/showproduct.php?prodid=CB-031-AK&groupid=701&catid=48&subcat= This should allow me to connect another 2 PWM 4 pin fans so my mobo has PWM control over 5 fans. The 2 extra fans are a Front Intake (HDD Cooling) and Side Intake (GPU cooling). As I want to have control of all my system fans, this cable could negate the need to buy a fan controller to manage these additional fans.

Can anybody tell me if the mobo software, to monitor PWM fans connected, will recognise the extended mobo headers/2 extra fans this cable provides?

Will the software display all 5 fans so I can monitor and manage all the fans from there?

Thanks!
 
pastymuncher said:
I think to get this working the two fans on the splitter will need to be exactly the same. Software will only show them as a single fan i believe.
Click to expand...

So the splitter just seperates the CPU side of the cable from the 2 additional input plugs, software will recognise CPU + 1 other PWM connected fan from the 2 inputs on the splitter?

Planning to use 2 x Akasa AK-FN057 Apache Super Silent 120mm fans but would really like independent control of each, so it looks like a fan controller too! Luckily I have a spare 5.25" Bay and I guess the Scythe Kaze Master will look preety cool in my case!

If, as in your answer, "software will only show them as a single fan...you think"...I can still buy the cable and use one head on the splitter to PWM my rear exhuast fan which I currently have no control over. As long as the software can recognise the extra fan as PWM and include it in the fan control menu selection boxes for me to adjust speeds/performance from there, I'm happy :D

Guess I'll have to try it, thanks for your reply ;)
 
The PC will only see one fan. Power is taken from the large 4 pin molex connector, the tach cable (RPM sensor) from one fan is connected to the mobo, the PWM cable (speed control) is split between all the fans.

All fans will be told to run at the same percentage of their max speed based on the RPM of whichever fan has its tach signal connected to the mobo header.
 
DigitalReaper said:
All fans will be told to run at the same percentage of their max speed based on the RPM of whichever fan has its tach signal connected to the mobo header.
Click to expand...

Thanks DigitalReaper...I think I understand you correctly?

If the CPU and 2 additional fans were connected via the cable, to the mobo header, the software will still only show the CPU fan for monitoring but all 3 RPM values will be changed in sync with any CPU fan adjustment I make? So it becomes a kind of 3 fan CPU Cooler.

Can I mix and match fan sizes, manufactures etc.? My CPU Cooler has a 92mm attached and my Rear Exhaust will be 120mm and I'm now thinking of adding a 120mm Top Exhaust to complete the 3 fan attachment to the cable.

I guess the criteria will be RPM values, I assume if they are all rated the same RPM speed irrespective of size & manufacturer, it will work?

I have read that 2 identical fans from the same manufacturer with the same RPM speeds quoted can actually vary somewhat in speed performance once installed, i.e., 2 x 2000RPM fans, 1 will achieve this max. another may only max at 1900RPM?
 
The fans can be different. The mobo requests the fans to run at x percent of their max speed rather than an explicit RPM.

Lets say you have a 2k and a 3k RPM fan connected up with the 2k one as master. The PC sees the fan running at 2k, then tells it to run at 50%, you end up with the fans running at 1k and 1.5k RPM

The speeds that identical fans run at can vary due to manufacturing tolerances but also how much resistance they encounter to airflow.

http://www.formfactors.org/developer\specs\REV1_2_Public.pdf :)
 
Last edited:
Excellent DigitalReaper! Thanks for all yr knowledge and expertise, I'm up to speed on this now...forgive the pun!...and thank you for posting the link for me.

I'm learning so much from you knowledgable folk on the forum and it's great to get the info. I need to do the jobs I want before buying the kit which saves me wasting both time and money...I've done too much of that in my life with our fairer sex :eek:...but that's a story is for another forum :D

Thanks again!
 
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