Does nVidia Optimus Completely Shut Down GPU?

[Axonn]

I've been wondering if Optimus COMPLETELY shuts down PCI Express power & all power to the GPU. I know that in Desktop systems we don't have that because of drivers & initialization of system (pre-BIOS), which is a pity.

But do laptops have this? If they do, why can't it be done for desktops?

If they don't, then what's the difference between Virtu and Optimus?

 

[StrangerGuy]

Optimus shuts down the Nvidia GPU completely when not in use.

 

[waffleironhead]

Optimus shuts down the Nvidia GPU completely when not in use.

This is true. The only issue I had was getting it to turn on when I wanted it to.

 

[Axonn]

So how come we don't have something like this on the Desktop? What is so different? They're the same chipsets on the Mobos and roughly the same mobo manufacturers I suppose.

 

[Phil L]

My guess is that the problem is probably the same as is with QuickSync and dGPU on Sandy Bridge desktop. Namely if you shut the power to the dGPU, there is no more display coming out of it, so you would have to have your monitor connected to the iGPU at all time instead. Then you would need something like the LucidVirtu but for power management purpose, which can also reboot the dGPU (and handle the BIOS issue) and pipe the display through the iGPU port. Probably not impossible to do but I guess the demand isn't that high for it?

 

[TakeNoPrisoners]

A lot of web browsers are GPU accelerated now, not to mention flash acceleration. If the iGPU can handle it no problem then this technology would be good. Otherwise I'd rather just have it idle.

On laptops where power consumption needs to be as low as possible it is worth it to have this enabled. On home desktops it is more important that the system is as powerful as possible, with power consumption not being as important because of the unlimited power supply they are connected to.

 

[taltamir]

So how come we don't have something like this on the Desktop? What is so different? They're the same chipsets on the Mobos and roughly the same mobo manufacturers I suppose.

nvidia and AMD both promised that since about 2008. It never materialized. They just don't care. Or rather, they feel that desktop users don't care enough about power consumption.
IIRC anandtech said that the hardware for optimus is available in all desktop GPUs from nvidia, but software is missing.

It might possibly be due to the issues with optimus. quick search of optimus on desktop and I find this nvidia forums thread:
http://forums.nvidia.com/index.php?showtopic=183643

Where basically everyone says the same thing "most buggy feature on laptop" and "too buggy to bring to desktop" basically.

First I heard about it too, from the anandtech review and others I got the impression it works perfectly with no known issues whatsoever.

 

[nenforcer]

nVidia called the "Optimus" technology on the desktop "Hybrid SLI" which was suppose to allow the onboard Geforce GPU on a nForce motherboard to handle all 2D / Desktop work while the discrete card would handle dedicated 3D gaming.

AMD has Hybrid Crossfire but I believe this refers to the ability to run Crossfire with different AMD GPU architecture chips. i.e. HD 5850 + HD 5870 in Crossfire.

I don't know what AMD calls the equivalent of nVidia Hybrid SLI on the desktop.

 

[Axonn]

taltamir: some people do care about desktop power consumption, and, as you said, it's a pity they don't care about us.

And I would hate to pull out my GPU for the 2 months when I'm not playing. I usually play in "stints" ::- ). So I might actually really go THAT far and remove GPU from the comp ::- D. If I have a Sandy Bridge GPU which can perfectly handle my software development needs, then why waste 11 Watts / hour for 16 hours / day on an idling GPU?

 

[taltamir]

taltamir: some people do care about desktop power consumption, and, as you said, it's a pity they don't care about us.

I know. I would have bought an optimus desktop card in a heartbeat.
For the silence, for the temperature, for the power savings...
It is they who think desktop users don't care... look at how loud, hot and power hungry high end cards are.

nVidia called the "Optimus" technology on the desktop "Hybrid SLI"

no, they had something similar but different to optimus called hybridpower
http://www.legitreviews.com/article/708/1/

But it is only available with:
1. Low end video cards.
2. Hybrid SLI
3. An nVidia IGP.

It is important to note that not all hybrid SLI setups had hybridpower as well.
And since nvidia discontinued their IGPs...

 

[taltamir]

delete

 

[waffleironhead]

nvidia and AMD both promised that since about 2008. It never materialized. They just don't care. Or rather, they feel that desktop users don't care enough about power consumption.
IIRC anandtech said that the hardware for optimus is available in all desktop GPUs from nvidia, but software is missing.

It might possibly be due to the issues with optimus. quick search of optimus on desktop and I find this nvidia forums thread:
http://forums.nvidia.com/index.php?showtopic=183643

Where basically everyone says the same thing "most buggy feature on laptop" and "too buggy to bring to desktop" basically.

First I heard about it too, from the anandtech review and others I got the impression it works perfectly with no known issues whatsoever.

The bugs most likely were in the form of the optimus profile not recognizing what was a game and what wasnt. They may have gotten this fixed recently though. It was painfully obvious when the laptop didnt switch from the igp over to the nvidia part. Games would not be running properly.

 

[Axonn]

I think such bugs could always be mitigated by manually specifying the (game or 3D program) executable somewhere in the nVidia Control Panel?