Request for help/advice in investigation of one interesting "huge FPS regression" bug

[Stefan Dösinger]

Am Sonntag, 15. April 2012, 07:22:34 schrieb Alexey Loukianov:
> When I configure an app to run in a windowed mode I've got around 40 FPS on
> game login screen with nVIDIA drivers 275.09.07, but switching into using
> more recent versions causes FPS to drop to around ~10.
It could be a driver bug as you suspect, which is difficult to track down - 
your best bet would be using something like oprofile to find out which GL 
calls show performance changes.

It could also be because of some additional features added in newer drivers. 
16 byte alignment for vertex buffers is a possibility, I believe it was added 
in the 280 drivers. You can check this by disabling GL_ARB_map_buffer_range. 
If this improves performance, you're probably running into a dynamic buffer 
related issue. It wouldn't explain the windowed vs fullscreen difference, but 
it's still worth checking.