Just wondering why this.
Working on a:
2x3.0 GHZ Quad-Core Intel Zeon
4 GB 667 RAm
This is runs about 60 ++ fps
ofSetupOpenGL(1680, 1050, OF_WINDOW);
I made a large screen just doing some test. This very very slow about 8 fps
ofSetupOpenGL(3360, 1050, OF_WINDOW);
When I have a 1680x1050 window and stretch it out with the mouse to 3360x1050 it is still fast about 60++ fps.
What graphics card does it have?
Also is you app doing anything at the moment?
on the addonsExamples/allTestExample at 3360 by 1050 with verticalSync off I get 1700fps
Intel Core2Duo 3.3Ghz Hackintosh with NVIDIA 8800GT
When the app is running you can play with your GLUT preferences by going to openFrameworks (menu) -> preferences.
If it is an ATI card you might have some luck downloading the ATI control panel which lets you play with some performance settings. http://aaron.gy/stuff/atidisplays
Also does it make a difference if you call
ofSetWindowShape(3360, 1050); in testApp::setup
and just ofSetupOpenGL( 640, 480, OF_WINDOW); in main.cpp