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Low power draw motherboard?

Posted: Tue Jan 09, 2018 5:40 pm
by TAMUmpower
Building my first folding PC, actually first PC from scratch ever but I've been around this stuff for awhile so not totally helpless. It's a 24/7 folding unit so no need to factor in any other use.

The goal, like everyone, is the highest PPD/Watt within reason. Based on the current charts I'm targeting a 1080 GPU and an Intel i3 6100t processor (the lowest power use I've been able to find). My question is apart from switching from an ATX to a micro ATX motherboard is there any way to assume one motherboard is a lower power draw than another? I don't see the specs published anywhere really. I'm assuming anything that says gaming on it usually isn't very power efficient

Re: Low power draw motherboard?

Posted: Tue Jan 09, 2018 8:10 pm
by jrweiss
Compared with the CPU and GPU draw, MoBo power draw is miniscule. With no other use, just buy the cheapest MoBo that you like; i.e., look at the brand and quality level that suits your budget and philosophy. You don't need extra USB, Ethernet, or SATA ports, or fancy LED lighting, along with their additional controllers that will add to power draw.

Re: Low power draw motherboard?

Posted: Tue Jan 09, 2018 10:24 pm
by rwh202
You can often turn off the extra features in bios - audio controllers, esata, FireWire, parallel/serial ports etc. for every last watt.

Don’t go out of your way for the ‘t’ series processors though. The difference in power draw is negligible during real usage and underclocking / volting a standard processor does a good job for less outlay. My skylake pentiums report 11W whilst driving pairs of 1080s (2.4 GHz I think).

Re: Low power draw motherboard?

Posted: Tue Jan 09, 2018 10:37 pm
by TAMUmpower
Thanks for the tips guys. So can any motherboard undervolt? Speaking just of the 6100 I believe the multiplier is locked so not sure if I could underclock it, just undervolt. Right?

Which pentium are you getting 11w out of? Just curious what the relation is to its TDP. Only reason I was mentioning the 6100t was because I wasnt really aware what the average processors power usage was when just running a GPU.

Re: Low power draw motherboard?

Posted: Tue Jan 09, 2018 11:22 pm
by rwh202
I think most boards / cpu can undervolt / clock. I thought locked just meant the maximum multiplier was locked but could otherwise be changed.

Pentium g4400, so a 54W tdp - that really is worst case, with the IGP being driven flat out and heavy use of memory, cache, FPUs etc. GPU folding puts relatively little strain - mostly just polling the pcie bus

Re: Low power draw motherboard?

Posted: Wed Jan 10, 2018 7:03 am
by TAMUmpower
Cool, you made me double check some stuff, I didn't realize the new pentium g4560 basically made the 6100t redundant so I got one of those on the way. Thanks for the tip off on the pentiums. Sorta forgot they existed lol, pretty sweet deal

Re: Low power draw motherboard?

Posted: Wed Jan 10, 2018 4:35 pm
by Nathan_P
The least amount of draw I've managed to get is 68w at idle for the total system, that's cpu, ram, mobo fans and 2 x gpu's, 1070 & 1050ti. That's goes up to 268w under load folding on both gpu's. I haven't yet looked at disabling unwanted mobo features yet though.

Don't forget to get a high efficiency power supply, 80+ gold at the very least.

Re: Low power draw motherboard?

Posted: Wed Jan 10, 2018 5:52 pm
by rwh202
With a G4400 and a pair of 1080s, my systems idle at 49W, fold at 300W from the wall (power limit set to 130W for each GPU - seems to be a sweet spot for power / performance). Gold/platinum PSUs and 240V from the wall help with my efficiency too.

Re: Low power draw motherboard?

Posted: Wed Jan 10, 2018 8:38 pm
by Nathan_P
Evidently I need to do some more tweaking as its only got a 25w tdp cpu in there....

Re: Low power draw motherboard?

Posted: Wed Jan 10, 2018 8:59 pm
by rwh202
Nathan_P wrote:Evidently I need to do some more tweaking as its only got a 25w tdp cpu in there....
First check whether your power meter is measuring true power - the power supply in a PC can present a power factor to the meter that means those that just multiply volts by amps (apparent power) over-read by quite a bit.

Re: Low power draw motherboard?

Posted: Wed Jan 10, 2018 10:18 pm
by jrweiss
My 3770S rig pulls 54W from the wall at idle (according to the display on my UPS), including monitor at standby and all audio and USB gear connected. HWMonitor sez the CPU pulls 50W at 100% load, vs the 65W TDP. Max system draw is 190W.

The 4770K rig doesn't use that much more power. In fact, it uses only 45W at idle (same caveats), and the CPU draws 56W max (stock clocks & volts) vs the 84W TDP. Max system draw is 260W (older, less efficient monitor).

Since you're going to run 24/7, look for the low end of the high range of MoBos. You want the good capacitors, heat sinks, and VRMs for reliability, but not all the fancy extras.

Re: Low power draw motherboard?

Posted: Sat Jan 13, 2018 8:35 am
by Nathan_P
rwh202 wrote:
Nathan_P wrote:Evidently I need to do some more tweaking as its only got a 25w tdp cpu in there....
First check whether your power meter is measuring true power - the power supply in a PC can present a power factor to the meter that means those that just multiply volts by amps (apparent power) over-read by quite a bit.
I use a kill a watt so anything is possible depending on how well it was made. It will show volts and amps so i'll check those and see if the wattage reading is correct

Re: Low power draw motherboard?

Posted: Sat Jan 13, 2018 5:57 pm
by bruce
The Kill-a-Watt measures true power.