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Old 04-14-12, 10:02 PM   #11
lexa2
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Default Re: Major FPS drop in Unigine Heaven (native linux binary) under dual-monitor Xineram

Plagman, from the very beginning this report was about the "huge FPS drop and nothing else", so yes, FPS drop is the only thing that's being observed here.

Thanks for clarifying the thing about "Xinerama = huge perf. hit", but IMO it would be great if this info would also be provided in docs bundled with nVIDIA drivers so end-users would be warned against using Xinerama. On a side note, as a programmer I can easily understand what causes perf. hit in case rendering context spans over two different screens (i.e. if a render target window is split between two screens composing Xinerama), but it's pretty strange for me that perf. is also affected severely when the render context is entirely bound to one of the Xinerama screens. Even more, I suspect that Unigine Heaven most likely uses offscreen FBO's to do it's renderings and blits results into X drawable afterwards, and I can't clearly see a reason for Xinerama to cause huge performance drop for a such case. On the other hand, I'm a not a GPU driver programming expert so my assumptions might be totally wrong.
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