X64 slower than Win32


Windows 7 64 bit Pro, VS2008:

When I build my OpenGL app in 32 bit, it renders at acceptable framerates, similar to XP, displaying a non-textured model with about 144K triangles.

When I switch to x64 and rebuild, the app runs at 1/8 the framerate!

I verified under 32 bit, it’s loading c:\windows\SysWOW64\opengl32.dll, and under 64 bit, it’s loading c:\windows\System32\opengl32.dll.

I have an Nvidia GTX470 and a 9800GT installed, it behaves the same on either card. The only thing I can think of is that I have the CUDA drivers installed instead of the normal Nvidia drivers, but I don’t think this affects OpenGL32.dll?

Is there something else I can test?

Thanks in advance,

I do not think it is related to x64 OpenGL.
Profile your application to find the bottleneck.

For example my application was slower because I was using C++ dynamic_cast<> too often. This casting is about 10000 times slower on XP x64 then on XP 32bit.

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