Disabling dGPU in Desktops - when will it be possible?

[boxleitnerb]

When will there be an Optimus-like technology in the desktop where the discrete GPU(s) will be (almost) completely shut off? Even though discrete GPUs at max only consume 25-30W, it is still a waste of energy, especially if you run a multi-GPU setup with 2-4 cards.

Not everyone has/wants a second computer just for surfing. It wouldn't be economically reasonable as the additional hardware and software costs (OS) would easily eat up any energy cost savings.

 

[tw1164]

Do you mean like Lucid Virtu?

 

[boxleitnerb]

Yes and no. Yes because you can use the iGPU, no because idle power consumption doesn't change a bit with Virtu as tests have shown. I would like to really disable the whole card(s) so they use no power whatsoever if possible.

It is possible in notebooks, why not in desktops?

 

[Claudius-07]

I agree. This really should be a priority since so much focus has moved on to power consumption/saving, heat issues, noise, price vs performance, performace vs power consumption etc. We don’t need those 2 overclocked 580 GTX’s running hard for surfing a few shopping sites and answering a few emails.

I am still debating the whole lucid virtu thing and thought it was brilliant of an idea but as you said, many tests have proven little to no savings in power.

I suppose however, that many current video cards have made improvements on their idle power consumption states. At least that.

PS if Lucid Virtu has gotten better in this respect via newer drivers etc, would love to know.

 

[know of fence]

Optimus switching really works like a charm on notebooks. And I do hope that it will be available with the next generation of cards. But there is no word out aside from a rumour avalanche from half a year ago.

Maybe the problem is that most boards don't support APUs, and that you can't really use some of the multi monitor set-ups with Optimus, which is a selling point for discrete cards. They also wanted discrete cards to be working all the time and alleviate CPU load by doing video acceleration, HTML 5, Cuda, much like with ION they allowed 1080p playback with an otherwise weak Atom processor using a discrete Video card.

I do hope that at least the midrange cards will support some kind of virtual OFF-switch.

 

[boxleitnerb]

Is this even possible with current PCIe technology? The card would have to switch on immediately if needed. Also, some kind of wake signal would have to be sent via the bus.

 

[ViRGE]

Is this even possible with current PCIe technology? The card would have to switch on immediately if needed. Also, some kind of wake signal would have to be sent via the bus.

Yes, it's possible. It's no different than current laptops in that respect.

The issue is that Optimus and similar technologies need to be validated; there's a fair bit of work that goes into the BIOS to make sure a select few GPUs it can be paired with properly power down and power up. Laptops are effectively sealed systems with no user-replaceable parts, which makes them easy to validate. With desktops however the GPU is easily replaceable, and that makes validation much, much harder.

 

[Herald85]

Right now you plug your DVI/HDMI cable in your Gfx card. Power that dedicated down completely and... you have no signal. You could perhaps plug in two cables, one on the dedicated and one on the onboard. But then you would need at least two DVI ports on your monitor.

 

[boxleitnerb]

Is that really necessary? Right now with Virtu or Optimus I guess the iGPU is connected to the monitor and the signal is sent from the dGPU to the iGPU and then to the display.

 

[Puppies04]

Right now you plug your DVI/HDMI cable in your Gfx card. Power that dedicated down completely and... you have no signal. You could perhaps plug in two cables, one on the dedicated and one on the onboard. But then you would need at least two DVI ports on your monitor.

After reading the thread this is exactly what I was thinking. I presume on a laptop with a fixed GPU and CPU you can put a physical connection between both outputs and feed whichever one is working to the output, how would you achieve this on a desktop setup?

 

[boxleitnerb]

See my post over yours. This is how it is done today. The only thing lacking is, that the dGPU (which is not connected to any monitor) is not really put to sleep.

 

[dorion]

After reading the thread this is exactly what I was thinking. I presume on a laptop with a fixed GPU and CPU you can put a physical connection between both outputs and feed whichever one is working to the output, how would you achieve this on a desktop setup?

Have some kind of pass through. Like, the GPU passes it's signal to a MUXer on the MB somehow and then the normal IO ports on the motherboard spits out which ever GPU is working. Whether that's an internal or external affair is up for the standards to decide. Whether or how the pass through can support multiple connector types is also for standards committees.

 

[Red Hawk]

Do you mean like Lucid Virtu?

Isn't it possible to connect the monitor through the mobo video output so the dGPU doesn't have to switch on at all unless it's told to?