Hi, On Nov 28, 2007 1:44 AM, Loong Hin <[EMAIL PROTECTED]> wrote: > I am running OSG in dual Nvidia 8800 GTS 320 MB graphics cards in SLI mode. > But I notice there is not any improvement in update rate whether I am running > in SLI or not. I wonder will OSG able to take advantages of SLI? Thanks.
SLI is all down to the OpenGL driver doing stuff being the OSG's back, it doesn't have any control over it, its all driver settings controlled. Whether SLI is possible to enable depends upon the type of OpenGL features the application is using, you'll need to read up on NVidia docs for the limitations. As for potential performance benefits, its all depends upon what you bottleneck is, if its CPU then no amount of extra GPU power will help, its is a bandwidth/memory limitation then SLI could well make it worse, if its vertex process throughput then its again unlikely to make any difference, if you a fill limited/fragment shader limited then you might just see an improvement with using SLI. Frustratingly the OSG is well conditioned for multi-thread/multi-context usage, so can use multiple CPU cores and multiple GPU efficiently - more efficiently than SLI can in fact, but unfortunately NVidia haven't published APIs for controlling the compositing backend used by their SLI implementation, if they did we could tweak osgViewer to use the dual cards to output to one display, and we'd see much better scaling of performance than SLI typically offers. Alas Nvidia is too used to trying to make games appear a couple of fps faster by any hacks possible, rather than actually wanting to work with the developer community to solve the scalability problem properly... Robert. _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
