GIGABYTE GA-EP45-UD3R CPU fan question?

[Keizer]

Greeting everyone! I just completed a PC build for my brother. This is the first time I have used a Gigabyte mobo. The system went together without any issues at all. Here is a run down on parts.

GABYTE GA-EP45-UD3R
Intel dual core CPU
WD 500 GB hard drive
ATI graphics card
Zalman CPU cooler
DVD RW drive
Corsair 620 wt PS

My question is this. When I first powered the system on, all the case fans spun up, but the CPU fan was completely still for about three seconds, and then started up. I went ahead and entered the bios to look around. CPU temp was a steady 20C the entire time I was in the bios. I went ahead and shut the system back down. Later, I started the system up again. Same thing, all fans powered up, but the CPU fan sat there for 3-4 seconds before spinning up to full speed.

Ok, I did some looking around in the mobo hand book, and found the "Smart fan control". I disabled that, but the CPU fan still sits for a few seconds before starting to spin. Once it's spinning, it runs nice and steady, and I can control the RPM with the speed controller that came with the Zalman.

Does anyone know why this happens? Is there some issue with the board? Could the CPU fan header be damaged?

Aso one other question. I originally had one of the case fans connected to the "SYS_FAN2" connection on the mobo. The fan connected to this header did not spin as fast as the other fans. I checked the RPM in the "PC health status" section of the bios to confirm this. I then connected the fan directly to the power supply, and it spins just as fast as the others. Is this fan header not getting enough voltage??

I appreciate any help on this!! Thanks!

[godto]

Re: GIGABYTE GA-EP45-UD3R CPU fan question?

i own few gigabyte mother board ... and yes they all start few second latter when boot up.

and your sys fan slow ... check the bios ... there is option to diable it ... because auto is raise the voltage when the mother get hot ...

[Lsdmeasap]

Re: GIGABYTE GA-EP45-UD3R CPU fan question?

Yeah all that is normal. If you set Smart fan control to disable then your CPU Fan will run at full speed always, if you enable it you will have to set method to Voltage as I believe your Fan is likely not PWM Fan

Since you are using your own controller it may be best to be disabled, and you control it. And yes, it may take a second or two to start with a controller that is normal and your CPU will be fine

SYS_Fan2 is often kinda buggy, some boards it does not work at all, others it is slow. It is a PWM Sensor Header is why, and if a PWM Fan is not connected it is controlled by a onboard sensor.

Here is the findings of one of our members about SYS_Fan2 >>>

SYS_FAN2 connector needs any fan, with three or four wires (don't care) since the speed is controlled via on-board PWM controller that supply pulse-width-modulated 12v for the fan via pin 2.

So, if using a four wire fan, its internal PWM is locked to full speed (this explain that fixed 5v on pin 4).

This time, the mobo senses the North Bridge (in my case the P35) temperature and will increase or decrease the speed of the fan connected in this socket. Feedback is sent to pin 3 for BIOS alarm purposes.

[Keizer]

Re: GIGABYTE GA-EP45-UD3R CPU fan question?

Since you are using your own controller it may be best to be disabled, and you control it. And yes, it may take a second or two to start with a controller that is normal and your CPU will be fine

SYS_Fan2 is often kinda buggy, some boards it does not work at all, others it is slow. It is a PWM Sensor Header is why, and if a PWM Fan is not connected it is controlled by a onboard sensor.

Thanks guys for the info!! It's always fun getting familiar with a new mobo. I will be my brothers only tech support, so I am doing my homework.

Above you mentioned that the CPU fan "may take a second or two to start with a controller". Does this mean that the Zalman controller is the cause for the CPU fan delay at boot up? Or would it have the same behavior if the fan controller was taken out of the equation??

Thanks!

[Lsdmeasap]

Re: GIGABYTE GA-EP45-UD3R CPU fan question?

Ya, all boards have their quirks for sure.

The CPU fan may take a second or two to start with or without a controller. A few seconds is nothing to worry about either way as the cooler (not sure which you have) is usually large enough to cool without the fan anway, but just not as good. So ya, a few seconds is nothing to worry about for sure

[Keizer]

Re: GIGABYTE GA-EP45-UD3R CPU fan question?

Ya, all boards have their quirks for sure.

The CPU fan may take a second or two to start with or without a controller. A few seconds is nothing to worry about either way as the cooler (not sure which you have) is usually large enough to cool without the fan anway, but just not as good. So ya, a few seconds is nothing to worry about for sure

So what causes the delay? Is it specific to Gigabyte boards? I have never had this happen on any other PC I have built. On all the other builds the fans all start right up as soon as you hit the power switch.

This board reviewed really good at Newegg. I read all the reviews and not a single person mentioned that the CPU fan has a delayed start up.

[Keizer]

Re: GIGABYTE GA-EP45-UD3R CPU fan question?

I guess I am just wondering why Gigabyte does the CPU fan delay at start up? It's not necessary, so why do they do it?

[Lsdmeasap]

Re: GIGABYTE GA-EP45-UD3R CPU fan question?

It is because of built in PWM Controllers I believe. Did you test yours without a controller on it? It may just be your controller, I have all water around here so I cannot remember for sure but I think a second or so is normal

And of course also test Smart fan disabled and or enabled w/ Mode voltage

[Keizer]

Re: GIGABYTE GA-EP45-UD3R CPU fan question?

It is because of built in PWM Controllers I believe. Did you test yours without a controller on it? It may just be your controller, I have all water around here so I cannot remember for sure but I think a second or so is normal

And of course also test Smart fan disabled and or enabled w/ Mode voltage

The CPU fan actually sits there for about three seconds before it kicks on. It's really consistent with this activity. Maybe it waits until the CPU warms up to a certain temp before kicking on?? That Zalman heat sink is solid copper and really big so I bet even with the fan not running for a few seconds, it absorbs allot of any heat created by the CPU. The PC runs great though, and I had it on all day yesterday loading the OS, and formatting the storage drive.

Yes I did try it without the Zalman controller, and it made no difference.

Currently, I have smart fan disabled, and the mode set to voltage. It doesn't matter if I have smart fan enabled, or disabled, the CPU fan sits for about three seconds before spinning on boot up.

I wonder if I should just hook the CPU fan to one of the 12v case fan headers on the mobo?? I bet it would start right up since the case fans do. I could always hook the case fans directly to the power supply. I already have two of the case fans attached to the PS anyway because there is not enough fan headers on the mobo.

[VorLonUK]

Re: GIGABYTE GA-EP45-UD3R CPU fan question?

My Intel stock fan does exactly the same. It seems to me that the bios goes through it's startup routine and once it reaches a certain point in the proceedings the fan then starts.

[Keizer]

Re: GIGABYTE GA-EP45-UD3R CPU fan question?

I really think that this delayed CPU fan start up is temp specific. As in, the CPU fan kicks in as soon as the mobo decides the CPU temp warrants it. Even with smart fan off in the bios, I believe that the mobo still uses CPU temp to tell the CPU fan to turn on at start up.

I built this system out on my shop work bench. It's rather cool out there, and that was where I was testing the system. Yesterday I brought the system in to the home office (warmer environment) where it sat all day and night. This morning when I booted up the system, the CPU fan had the usual delay, but it was only about 1.5 seconds.

[rberger]

Re: GIGABYTE GA-EP45-UD3R CPU fan question?

Greeting everyone! I just completed a PC build for my brother. This is the first time I have used a Gigabyte mobo. The system went together without any issues at all. Here is a run down on parts.

GABYTE GA-EP45-UD3R
Intel dual core CPU
WD 500 GB hard drive
ATI graphics card
Zalman CPU cooler
DVD RW drive
Corsair 620 wt PS

My question is this. When I first powered the system on, all the case fans spun up, but the CPU fan was completely still for about three seconds, and then started up. I went ahead and entered the bios to look around. CPU temp was a steady 20C the entire time I was in the bios. I went ahead and shut the system back down. Later, I started the system up again. Same thing, all fans powered up, but the CPU fan sat there for 3-4 seconds before spinning up to full speed.

Ok, I did some looking around in the mobo hand book, and found the "Smart fan control". I disabled that, but the CPU fan still sits for a few seconds before starting to spin. Once it's spinning, it runs nice and steady, and I can control the RPM with the speed controller that came with the Zalman.

Does anyone know why this happens? Is there some issue with the board? Could the CPU fan header be damaged?

Aso one other question. I originally had one of the case fans connected to the "SYS_FAN2" connection on the mobo. The fan connected to this header did not spin as fast as the other fans. I checked the RPM in the "PC health status" section of the bios to confirm this. I then connected the fan directly to the power supply, and it spins just as fast as the others. Is this fan header not getting enough voltage??

I appreciate any help on this!! Thanks!

I'm so glad you posted this! My CPU fan is a 4-pin PWM fan that comes with a Xigmatek HDT-S1283, and it doesn't spin up immediately from a cold start. It freaked me out initially, I thought maybe I had a bad fan.

I asked Gigabyte support about this ... like you, I thought maybe the CPU fan header was defective or wasn't getting enough voltage to start the fan. Gigabyte didn't say anything about a delay being normal, they just said to disable CPU Smart Fan Control for troubleshooting. As you discovered, the CPU fan doesn't spin up immediately even if you do that.

This is my first Gigabyte motherboard, and I've never seen this behavior before.

I've been giving my CPU fan a little manual spin after I press the power button, and I thought that's what's been gettting the fan spinning. Now I'm going to try just leaving it alone to see whether it starts spinning on its own after a little delay. However, I'm sure mine doesn't start spinning on its own after just a few seconds. I've been too nervous to just let it sit there without spinning, even with such a big tower cooler. The temp sensors on my E8500 are stuck and I don't know whether I can trust the temps reported by the BIOS.

If the BIOS (I'm using F4) is designed to start the CPU fan in response to
some temperature reading, Gigabyte needs to document it or at least say something about it in response to a tech support inquiry.

My CPU fan doesn't stop during a reboot, so at least my problem is confined to initial power up. It still made my heart sink in disappointment the first time I turned on my new build.

When I use SYS_FAN2 for a case fan (4-pin Scythe S-Flex SFF21E) it starts as soon as I hit the power button. So I tried plugging the CPU fan into the SYS_FAN2 header ... but the CPU fan still doesn't spin up immediately at power on. That's why I thought maybe I had a bad fan. Anyone have an explanation for this?

Anyway, I still don't have this resolved and I'd appreciate any ideas you guys have. Thanks.

[SpeedEuphoria]

Re: GIGABYTE GA-EP45-UD3R CPU fan question?

same thing here w/ my S1283

[pirate]

Re: GIGABYTE GA-EP45-UD3R CPU fan question?

ok, I have the same mobo with a pair of PWM fans (arctic cooling AF 12025) connected to the sys_fan2 header. I've set CPU smart fan mode to PWM and the fans only twitch a little. They do not spin up at all.

I've variously set cpu smart fan control to: enabled, disabled and auto without any change.

The cpu fan is a zalman cnps9500 connected to the cpu fan header and it runs fine, no issues. I'm running bios F6.

speed fan shows the offending fan header as fan2 and it's 0.

Is this normal? I'm running a q9650 and the temps are 30 - 32C

I would expect some speed but not 0.

Any ideas?

Thanks!

[Lsdmeasap]

Re: GIGABYTE GA-EP45-UD3R CPU fan question?

Speedfan is a terrible program to try to guage something like this. I know it is made for that, but I just find it to be terrible unless you have a specific file for your board, which I am not sure there is for this board yet?

Anyway, do you see the fan spinning at all? I would guess not since you said not, just wanted to be sure since you said you was checking anyway on RPM's with software

Some boards have faulty SYS_FAN2 headers, you may want to move that fan to another slot. And I would also switch the Fans to move that one you are having issues with to the CPU fan slot, just to be sure it and the PWM Function on it is not faulty.

Does a normal fan spin for you on SYS_FAN2 header? That would be a good way to see if your header is faulty. Some do take a a little bit to start up, so dont try for only a second or two and decide it is not working