Multi-Gpu question

[cdrgary]

So i've seen a lot of guides on SLI and Crossfire, but very little on how multi-gpu functions outside of that.
I know, for example, you could take a 9800 GT and a 9500 GT stick both of them in the same computer and hook a monitor up to each and do dual monitor that way. Same with mixing any ati cards, or even nvidia with ati cards.

My question is on performance.
Does each monitor hooked up to each separate card still get full 3d acceleration? I know the cards output a picture just fine, but could you play two separate games on two separate monitors hooked up to two separate cards and still get full performance from each card on its respective monitor?

And furthermore would GPGPU applications still recognize the cards?
In particular, would applications like SETI@Home recognize two separate Nvidia cards and be able to run one CUDA instance on each?

Furthermore assume that the board fully supports two full x16 links, but doesn't support SLI in any way.

Sorry for the rather ridiculous set of questions, but after searching for an hour, I've found no information on any of this.

 

[COLGeek]

Will give it a shot....

Assuming you have your drivers installed properly, you would indeed have full 3d acceleration with both GPUs. However, since you only have one PC, you wouldn't be able to run 2 games independently (as I think you are inquiring). You could run both games in windowed modes, but you still only have a single mouse and keyboard for inputs.

SETI would likely run separate instances for each GPU it identified in the system.

In your example, SLI is not a consideration as the 2 cards aren't operating in SLI (or can't for that matter). Having 2 x16 slots just means the GPUs have wide data paths.

Might be an interesting experiment, but I am not sure you will see a lot of performance gained by having a 9800 GT and 9500 GT installed in one system, except to make one of them your PhysX card and to use the other to drive 2 monitors.

 

[cdrgary]

Thanks, the cards mentioned were hypothetical, it would more likely be a 460 and a 250. Also, the inputs aren't an issue, many mmos and strategy games, or at least the ones i have in mind, could easily be played in the time waiting to respawn in tf2. the benefit comes from simply running them and being able to monitor them. Also, I don't think PhysX works on non Nvidia approved motherboards, hence the "assume board doesn't support SLI"

 

[jefe323]

it is possible, but you might run into performance issues

 

[jyjjy]

Physx works on any Nvidia card regardless of your motherboard.
The issue with running two games at once will be that they are both running on one CPU. This may be an issue depending on the CPU and on which games you are running. FYI I don't even think you would need 2 cards to do this technically although then they would also be sharing the GPU which would further hurt performance.