Z77X-UD5H : System fan headers - curious behavior

[fastie]

I've been experimenting with the system fan connections, initially with the intent of temperature controlling two front PWM (4-wire) fans on my Lian Li case so that it remains quiet unless I load it up.
I thought it worth mentioning that the four system fan headers on this board seem to behave differently.

I have four identical PWM fans so I was able to test all four headers independently or together.

Connected to SYS_FAN1 header, a fan seems to run quite slowly, (say, 700rpm at ambient) although it is controlled with temperature.
Connected to SYS_FAN2 header, a fan runs about twice as fast (say, 1400rpm at ambient) also controlled.
Connected to SYS_FAN3 header, a fan runs the same as SYS_FAN2.
Connected to SYS_FAN4 header, a fan seems to always run at full speed, uncontrolled.

It seems odd that they are different.
I'm using BIOS F5 at present. Setting system fan mode to SILENT or NORMAL etc does seem to vary the speeds of Fan1,2 and 3 proportionally, but they remain different.
Disabling fan control entirely makes them all run at full speed, and swapping them around proves that it's not the fans that are different.

Does the system expect a different type of fan on each header, or perhaps it is applying a different slope PWM to each of the headers for some reason?
Or maybe even a BIOS bug ? It's all a bit strange.

Of course I can persuade the two front panel fans to run at the same speed by bodging them both on to one header circuit, but I'd still like to understand what the board is supposed to do.

I note that the pin connection descriptions on page 27 of the manual vary slightly between the four headers, but this doesn't help at all; I don't know whether that may even be a typo.

[boondocks]

I can verify Sys_4 runs wide open. I had my rear pwm fan (pull on Zalman cooler) running wide open and I finally moved it to Sys_2. I don't see much movement on any fan except cpu. (Well the Zalman pump is connected to Sys_3 header but it doesn't seem to change)
So yeah, it's pretty strange. You'd think a pwm fan would show some movement for sure. I haven't tried any other settings. I'll check it out further soon.

[thetanine]

Yep I noticed this too, its been like that for every BIOS I have used so far. Annoyed me too.

[Acebmxer]

Yes for what ever reason Gigabyte sets sysfan_2 to half speed for what ever reason. I dont know if other MFR's do this but it seams Gigabyte has done this on all their motherboads.

Here is a very good $30 fan contoller I am using it my self and its great. Sunbeam Rheosmart 6 Fan Controller at Xoxide!

[Darkje]

That is odd... in Z77X-UD5H Preview/Physical Review sin sayed: "#5. iTE8728F is a SuperI/O that we commonly find on all GIGABYTE boards, on this board it provides all 5 fan headers and control over them. It also provides temperatures, voltage, and fan speed monitoring."

and now it is the same old show all over again?

[boondocks]

The concern I have is how to properly determine which header to plug my cooler pump into. Right now I have it in Sys_Fan3 header and hwinfo shows rpm of around 1442. I don't know if rpm correlates accurately with the actual pump speed but that seems pretty fast. You guys with liquid cooling have some feedback?

Basically right now I have with quick IBT test:
Front Fan -200mm Sys_Fan1 / 800rpm rpm drops a little under load
Rear Fan - 120mm Sys_Fan2 / 712rpm increases slightly under load
Zalman cooler pump Sys_Fan3 / 1442rpm increases about 20 rpm under load
Top Fan - 200mm Sys_Fan4 / 656rpm MOL steady at load
cpu fan - 120mm cpu_fan / 1025rpm at idle but increases with load as I would expect

The other thing is the cpu fan is of course on the radiator, and the radiator is basically mounted to the rear fan/case. Wondering if I need to match speeds of these fans for optimal results or possibly run rear fan faster? These 2 fans aren't matched, one came with the Zalman (pwm) and the other is a vortex (pwm).

[Acebmxer]

To run a push pull fan setup you will see better resualts using identical fans. This way one fan is not fighting the other.

[boondocks]

Sure. I'm going to see if I can match up some fans from what I have here.

Do you run your pump off your fan controller?
Thinking about picking one up. Didn't want to spend any more money but it would simplify things.

[Acebmxer]

Sure. I'm going to see if I can match up some fans from what I have here.

Do you run your pump off your fan controller?
Thinking about picking one up. Didn't want to spend any more money but it would simplify things.

My pump uses a mulex connector and has built in speed control which stays on full speed.

[boondocks]

My pump uses a mulex connector and has built in speed control which stays on full speed.

I'm not up on the jargon, mulex, ziptie, etc are all foreign words. I did figure out wormdrive, I think, known to me as a simple hose clamp?
From what I've seen the Zalman is running pretty close to wide open even at idle. Don't know just guessing from the rpm readout.
I got my other Vortex pwm fan and now their in push/pull, truthfully only I can rear mount is to have something behind the radiator anyway. Tried top but didn't like it. Actually the rear fan is running faster than the other one at idle but that should not be a hindrance, I'm thinking. When they crank up hopefully the speeds will match pretty good. Got to run some tests see if cooling better now that I rearranged things and added a 200mm side fan.