Sandy Bridge/ Z68 IGPU question

[NeoAnti57]

Hey guys, gotta wierd question here.

Just built my new rig- i5 2500k, Asus z68 chipset mobo, 560ti.

My buddy built a similar setup a month or so ago and was having issue after issue. He claimed that the IGPU wasnt allowing his dedicated GPU to take over when games loaded which resulted in crashing bugs/etc. I immediately asked him wtf he was talking about, he says that with sandy bridge and z68 the igpu and dedicated card are both used automatically, igpu in low states such as 2d/desktop and dedicated card is used in the 3d apps such as games/editing etc. I poured over the internet and read through my mobo manual twice and so far I cannot find any evidence to support what he is saying. It would seem the overal verdict is- Whichever video connector your hooked up to, either dedicated card, or igpu, is what the system will use for its video card. Unless your setup is using some third party software like Lucid(asus) which does indeed automatically switch between the two.

To say the least, im confused. Anyone care to clarify this whole thing for me?

[harlequin]

......

[powerarmour]

It would seem the overal verdict is- Whichever video connector your hooked up to, either dedicated card, or igpu, is what the system will use for its video card. Unless your setup is using some third party software like Lucid(asus) which does indeed automatically switch between the two.

To say the least, im confused. Anyone care to clarify this whole thing for me?

Yes, when the Lucid Virtu software is used, the system with use a combination of iGPU and dGPU depending on how you set it up in the application. So you can have the iGPU running 2D, with the dGPU idling/off, and then in 3D the dGPU can take over. You just need one DVI/HDMI connector connected to the iGPU port, as the dGPU goes through the iGPU's frame buffer, there is also a slight performance penalty to doing this though :-

http://www.anandtech.com/show/4199/l...idge-platforms

[red_dog007]

Shoot, what is the point?
Any dedicated card that one can buy today is going to have very low idle states. No point in having the igpu turn on to save a few watts at max.

Plus I would imagine that keeping it off 24/7 would result in slighter higher overclock and/or lower temps.

[powerarmour]

Shoot, what is the point?

Being able to use QuickSync video encoding/decoding for a start, especially if you want to convert 1080p media at the speed of the gods.

[Jarnis]

Problem with Virtu is that if you use the virtualized (iGPU) mode, some games require Virtu software update to work right.

If you pipe the pic out of the dedicated GPU, this isn't an issue.

In both cases if you have Virtu present, you may run into issues where wrong GPU is detected by various software. A game might have a hardware check at the start and say "go home" when it sees the epic fail HD graphics (workaround being "force system to use dGPU at all times")

It is a great system for saving power on a setup that is rarely used for games but I wouldn't enable it for heavy gaming rig, just to cut down on potential issues.