Triple Monitor Low Power PC

[Lope]

I'm building a jaw droppingly awesome low power server thanks to some help from this forum
(I'll share the details of it when all testing is done)
Its so awesome I'm considering building another one to replace my desktop PC.
But now I've hit a speedbump. I want 3 monitor capability.

The motherboard I've chosen is G31 chipset with a single VGA output which can run simultaneously with a PCIE gfx card.

I realize I could choose one of the new AMD boards with onboard 'Triple output' graphics, but they aren't actually 'triple output'. The HDMI and DVI connectors are the same port, you can't use them both simultaneously, so I'd still need a graphics card with that solution.

I've done some tests with a MSI Geforce 8400GS (passive heatsink)
It gets damn hot without any airflow.
With 1 graphics output running from the card it draws 9W.
With 2 graphics outputs the card draws 10W.

Underclocking:
Using latest nVidia drivers (197.45 x64) and NVidia system tools 6.06.
Default: core 567, mem 400, shader 1400
Underclocked: 141 100 350

GPU Power consumption only dropped 1.5 or 2W.
Considering an under-voltmod...
Then the power consumption of the card should drop from 8.5W down to about 3W hopefully. (I've got no idea)

Can anyone shed some light on the triple monitor issue?
I looked at other cards, like the ATI Firepro V3700 for $82with dual DVI, but its got a big heatsink and fan, so will probably use more than this 8400GS at stock. The Firepro 2460 is really nice (4 displayport (would need converters)) but it uses 13W which is worse than this 8400GS for my requirements.

Anyone undervolted gfx cards? how much of a power saving can you get?

--
All my power measurements are done by measuring current on the actual PSU rails, intercepted between the PSU and motherboard.

[MikeC]

I looked at other cards, like the ATI Firepro V3700 for $82with dual DVI, but its got a big heatsink and fan, so will probably use more than this 8400GS at stock. The Firepro 2460 is really nice (4 displayport (would need converters)) but it uses 13W which is worse than this 8400GS for my requirements.

Just a few watts worse... but against the power consumption of 3 monitors, this seems a trivial concern.

[Lope]

it all adds up mate monitors can be turned off...
sometimes I watch a movie on 1 monitor. or just do something on 1. if I get into heavy use I turn on a 2nd or 3rd.

If anyone here is good with voltmodding, I need a bit of help
http://www.overclock.net/graphics-cards ... 400gs.html

[Lope]

Made good progress on the undervolting mission...

[Lope]

Finished undervolting my 8400GS. Underclocking and Undervolting reduced power consumption by 22%.
Not as good as I hoped for, but good experience.
http://www.overclock.net/graphics-cards ... ost9550329

[Lope]

I'm building a jaw droppingly awesome low power server thanks to some help from this forum
(I'll share the details of it when all testing is done)
Its so awesome I'm considering building another one to replace my desktop PC.
But now I've hit a speedbump. I want 3 monitor capability.

The motherboard I've chosen is G31 chipset with a single VGA output which can run simultaneously with a PCIE gfx card.

I realize I could choose one of the new AMD boards with onboard 'Triple output' graphics, but they aren't actually 'triple output'. The HDMI and DVI connectors are the same port, you can't use them both simultaneously, so I'd still need a graphics card with that solution.

I've done some tests with a MSI Geforce 8400GS (passive heatsink)
It gets damn hot without any airflow.
With 1 graphics output running from the card it draws 9W.
With 2 graphics outputs the card draws 10W.

Underclocking:
Using latest nVidia drivers (197.45 x64) and NVidia system tools 6.06.
Default: core 567, mem 400, shader 1400
Underclocked: 141 100 350

GPU Power consumption only dropped 1.5 or 2W.
Considering an under-voltmod...
Then the power consumption of the card should drop from 8.5W down to about 3W hopefully. (I've got no idea)

Can anyone shed some light on the triple monitor issue?
I looked at other cards, like the ATI Firepro V3700 for $82with dual DVI, but its got a big heatsink and fan, so will probably use more than this 8400GS at stock. The Firepro 2460 is really nice (4 displayport (would need converters)) but it uses 13W which is worse than this 8400GS for my requirements.

Anyone undervolted gfx cards? how much of a power saving can you get?

--
All my power measurements are done by measuring current on the actual PSU rails, intercepted between the PSU and motherboard.

[BillyBuerger]

I've got a triple-monitor setup at work by using an AMD 780G motherboard plus an HD3650 GPU. One DVI on the MB + 2 DVI on the GPU. The 3650 is a fanless model which is nice. But it sits very close to the mini-Ninja CPU cooler which doesn't leave much room for the chipset heatsink to get airflow so it runs pretty warm. Still planning on adjusting fans around to see what will give some more airflow near the chipset. But overall it works great.

Where are you getting your GPU power numbers from? It looks like you're measuring power at the PSU DC output side for your own card. What about the other cards you mention as having higher power draw? Seems there's a lot of ways to get power consumption figures and unless you use the same for all, you might get conflicting results. Plus every card is going to measure differently due to sample variance. Just curious.