Supermicro X9SCM with PWM Fan for CPU?

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hotzen

Limp Gawd
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Jan 29, 2011
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349
Hello,

has the supermicro a decent working PWM-controller for the CPU-fan or is normal 3-pin recommended over 4-pin PWM?

Thanks
 
I used the stock cooler with I presume a 3 pin fan (have not cracked the case again to confirm) and the CPU temp is listed as "medium" which annoys me.

EDIT: used in a Supermicro chassis SC936A-R1200B which has 5 fans that are 4 pin. The X9SCM doesn't have enough fan connections on the board so I used a GELID Solutions 350 mm PWM Y Cable Model CA-PWM http://www.newegg.com/Product/Product.aspx?Item=N82E16812718001 and don't seem to have any fan speed weirdness on the other fans. Their RPMs list numerically and not just "medium".
 
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I had issues with my SUPERMICRO MBD-X9SCM-F-O LGA 1155 Intel C204 Micro ATX Intel Xeon E3 Server Motherboard + 8x Scythe Kama FLEX PWM 120 SA1225FDB12H-P 120mm Case Fan, the mobo manage to drop them very low, but then freaked out and ramp them up to 1600, and this was an endless cycle every 30sec, happened in all 5 different mobo headers, i tried to see if i could do something with speedfan, but wasn't sticking, but the issue was so annyoing that i switched all my fans to 3pins. Not sure if it was a bad mobo, but i seen other models on supermicro with that issue also, just google it. I never used the intel stock cpu fan nor anyother pwm fan on the X9SCM, so i cant say if it was the scythe fans, but the scythe fans work really well in HTPC, all spinning at below 300rpm and the mobo never freaks out.
 
@Abula:

I experienced the same issue with my X9SCM-F motherboards. So I contacted SM and they were kind enough to give me a custom BIOS for testing. I have been talking to them about this issue for quite some time and the reason you experienced the ramping on your fans is due to the fact that you are using fans that have a low minimum rpm and the BIOS is expecting a higher minimum rpm. SM tests and builds their systems with more powerful and higher speed (rpm) fans. IIRC, the minimum rpm is set to 700 (hard coded into the BIOS) and once your fan drops below this threshold, the BIOS will rapidly force the fan to maximum rpm and then slowly ramp them down again; The cycle starts over once the minimum threshold is reached again.

You can get speedfan to override this, but you need to keep the fans running above the minimum (lowest) threshold point. As long as you have speedfan configured to keep them running at that speed, you should be fine.

I believe that the latest BIOS version for the X9SCM-F includes some of the fan control modifications I requested. There are still some options I would have liked to see in the BIOS and hope that they will eventually make it's way into the BIOS.

One of the recommendations I gave them is to have an additional option in the BIOS to allow the user to change or program what that minimum rpm threshold should be rather than have it hard coded into the BIOS, that would have solved your problem easily!

The other request I had for them is S3 support for the BIOS. The original BIOS version (I believe that was 1.02) had a few options but I don't think it actually had full support for S3. In any case, the following BIOS version(s) had all those options removed :(

BTW: The 5 fan headers on the X9SCM-F all have independent RPM feedback, but only two PWMs are actually used to control them. FANA (for the CPU) is on PWM1 and FAN1 to FAN4 is on PWM2.

Hope this helps.
 
@treadstone, thanks for your detailed post,

I wrote to Supermicro about it, but never got an answer back, i started to get annoyed about the issue and started searching on the net for a fix, but only saw more cases like mine (not a lot) but with the exact same behavior on other chipset even, so i thought was a bios design defect.

For me wasn't that big of deal cause i had a HTPC build coming, and i knew ahead of time that the fans would work fine on the intel q67 mobo as this was the mobo that i first tried to use for my server, for other issues (long story), i decided not to use it for the server and went with Supermico,

I really wanted to use PWM fans, and the board seem ideal with 5 headers, but for the ramping issue, decided on goign with 3pin fans, 120mm Noiseblockers 750rpm for case fans + 140mm 700rpm fan, at the end its working really good, i wished i could have more rpms in case it need them, but wasnt pattient enough.

But your post is very clear into why the problem is happening, and will be useful for anyone going the route of pwm fans, Hope Supermicro in the future starts testing with other fans, specially fans that are capable with low rpms, the intel approach is very basic but functional, they only have minimum rpm values on their bios, and it works fine.

Thanks again for your post, really comforting to see that i wasnt the only one dealing with this issue on the X9SCM-F.
 
treadstone said:
The 5 fan headers on the X9SCM-F all have independent RPM feedback, but only two PWMs are actually used to control them. FANA (for the CPU) is on PWM1 and FAN1 to FAN4 is on PWM2.
Click to expand...
Sorry to necro this thread, but I found this via a somewhat-related google search, and thought I'd point out that this is backwards. Per Supermicro:

FANA is for add-on card and controlled by system temperature. FAN1~4 is controlled by CPU temperature. CPU Heatsink fan should not be connected to FAN-A. CPU Heatsink fan can be connected to FAN-1. Chassis fans can be connected to FAN-2~4 or FAN-A.
Click to expand...

Hope it helps someone.
 
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