SM XeonD boards and their molex + 8pin + 24pin Power connectors

Notice: Page may contain affiliate links for which we may earn a small commission through services like Amazon Affiliates or Skimlinks.

james23

Active Member
Nov 18, 2014
441
121
43
51
I just got my SM X10SDV-2C-TP4F (flex ATX , 2core PentiumD chip, very similar to Xeon-D chips). And im a bit confused on the various power ports / options on the MB. ( after reading closely in the manual, i think i may be lucky i didnt fry my board already!)

According to the manual, that 4pin MOLEX power port (# 3 in my pict) is ONLY for powering a HDD, nothing more.
And in terms of powering the MB itself, you should ONLY use EITHER the 24pin atx (#2) OR the 8pin connector (#1) but NOT both (#2 and #1).
mb pict Capture.JPG

Does anyone have any info on this or realworld experience with these power options on these board types (ie what are you using to power it?). im pretty sure ive read other threads where users are using both 24pin and 8pin, as i was researching this board here on sth.

When i first got the board in, on my test bench, i connected both the 8pin and the 24pin to my power supply (as you would on a normal server type board). I then ran memtest for about 22hours, with no issues.

Then as a test i tried connecting ONLY the molex 4pin to my power supply (+ using one of those 24pin shorted pin13 plug/connectors to power on the psu). This worked! the MB power button would not work, but i was able to power on the board via IPMI and run memtest for about 20min (FWIW, the power draw was 4w less using this, ie 50w vs 55w when running memtest86 pro v8's load). im using a PSU i had laying around, a 650w psu, so its def. not efficient at these low load levels, ofcourse.

here is the relevant page from the SM manual for this board. (i find it weird that you are NOT supposed to connect both 8pin and 24pin)

thanks
manual page.JPG
 

Attachments

hjfr

Member
Nov 21, 2013
79
20
8
France
What's the problem ? Do what is indicated in the manual : 24 pin or 8pin for powering the MB.

I have a X10SDV-4C and same thing in the manual: 24 pin or 8pin. I use 24 pin only.

It's allow various possibility of powering (standard ATX, 12v only, etc) for different installation environment.
 
  • Like
Reactions: james23

Arvind Sankar

New Member
Dec 6, 2018
5
2
3
To add to that, their mini-chassis (i.e. the E300) uses just the 8-pin connector to power it using a 12V DC brick. Regular chassis/PSU uses the 24-pin. Note that it also works with just a 4-pin installed into the 8-pin connector, or a 20-pin in the 24-pin connector. I definitely wouldn't try powering it using the 4-pin molex header, that is supposed to be used as a power output for powering a hard drive/ssd in the min-chassis (I think the mini chassis comes with the appropriate cable to do so).
 
  • Like
Reactions: Patrick and james23

PigLover

Moderator
Jan 26, 2011
3,183
1,543
113
Can confirm first hand - powering from the 4-pin/8-pin (depending on board) works just fine and is the design intent. Some of their newer boards don't even include the 24 pin connector at all. This makes sense because more and more of these boards are being installed into embedded or mini systems where a full ATX PSU (or its server chassis equivalent) does not make sense.
 
  • Like
Reactions: james23

james23

Active Member
Nov 18, 2014
441
121
43
51
cool, thanks for the replies.

if one uses just the 8pin atx (or half of that 8pin atx), (assuming using a normal, full SM server power supply), how do you switch the PSU itself on /off? ie- i know that a 24pin atx connector has pin 13 which when grounded turns the PSU on (no ground = turn psu off), but do 8pin atx plugs/wiring have this on/off ability too? (i assumed no)


(hjfr- tks for reply/info- i do plan on following the manual exactly, but the reason i was asking about all this, is better understand , but also as im trying to see if there is a way i can share a 2u SM chassis's PSU between its expander backplane and this board (while the backplane is connected to a different NAS server, not this xeonD board). <- im really just experimenting, this is not something i will run in my lab for obvious reboot/shutdown reasons. ill mostlikely leave the chasis psu for the backplane with a physical on/off switch, and add a 2nd picopsu or other psu just for this xeonD board, all in same chassis. )

thanks
 

Patrick

Administrator
Staff member
Dec 21, 2010
12,508
5,786
113
With the DC power option, you are using the front panel header to turn the system off. The PSU itself is usually a power brick and will just run.

If you are using a small 1U like the 5xx-203B, you would have a part to jumper the PSU to on, and then the CPU power connector installed.

It is pretty easy.
 

Arvind Sankar

New Member
Dec 6, 2018
5
2
3
With the DC power option, you are using the front panel header to turn the system off. The PSU itself is usually a power brick and will just run.

If you are using a small 1U like the 5xx-203B, you would have a part to jumper the PSU to on, and then the CPU power connector installed.

It is pretty easy.
But if you're using the 5xx-203B you might as well connect the 20-pin cable instead of messing with the jumper trick?

Edit: oh just saw james23's comment on the 2u chassis hack