Emulator

What steps will reproduce the problem?
1.Run zelda twilight princess with opengl plugin
2.You will receive 5-7 fps at some stages of the game even with modern
gaming pc
3.Then run the game with directx and you get about 20 fps at same areas
which is about 300 % faster

What version of the product are you using? On what operating system?
As far as I know,this issue is present in all revisions and on all
operating systems

Please provide any additional information below.
It is understandable that some games will run at different speeds under
different gpu plugins. However,I find that 300 % difference is a bit odd
and probably a bug in opengl plugin