Hi Mathieu, I haven't tried SLI yet, but I have read some docs from NVidia about getting best performance from SLI and it looks like they don't want to app to do things like using glViewport which the OSG does, there are a few other odd cavates. I suspect NVidia and ATI have various driver detection hacks to tweak things for games to twist things to their own rules.
SLI is basically a hack to make single threaded, single graphics context applications work on two graphics cards. It's shoddy way to do things that only can help in fill limited apps. Its much better to do this type of management at the scene graph level, something that the OSG is capable of, and particularily well suited for taking advantage of multi-core CPU and dual GPU machines. The only stumbling block is that the compositing that SLI does is not something that has extension to support yet, and this I find *very* frustrating. Personally I'm pretty appalled by the literature that NVidia has pushed out about SLI, they recommend things like disabling Vsync to prevent the latency of AFR(alternative frame rendering) from killing response times, yet never mention about the bad effects it has on visual quality. What is the point of being able to double anti-aliasing for better visual quality if you visual quality is destroyed by tearing? Its totally taking the piss, a clear indication that marketing driods have won the battle. Its so sad that such great hardware gets sucked off with nonsense like this, rather than messing around with hacky drivers to get slightly better frame rates with vsync off they should spend their time on exposing extensions to help us graphics professional make use the best use of their hardware. Robert. On 3/5/07, Mathieu MARACHE <[EMAIL PROTECTED]> wrote:
Hi all, I've looked throughout the mail archive for a explicit use of SLI (2 cards for one output) and didn't find any, the only use found is 2 cards 2 outputs. I did some testing under Windows and Linux and neither tests did have any noticeable acceleration using any of the SLI modes (AFR or SFR) Did anybody tried to use OSG in SLI mode and thus was able to have noticeable acceleration or is this a 'feature' and OSG can't by design use SLI configurations ? -- Mathieu _______________________________________________ osg-users mailing list [email protected] http://openscenegraph.net/mailman/listinfo/osg-users http://www.openscenegraph.org/
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