Dual-Head multi-display and OpenGL Games incompatibility?

[Prizm]

Does anyone with a Dual-Head board had any problems diplaying a OGL game on a TV in the clone mode?

I have a G400MAX and it has allways worked fine in dual-head mode with my TV (DVD's, Direct3D games, desktop clone...) except for OGL games! I get big annoying flickering on the TV screen but not on the PC monitor. And the flickering mainly happends in the bottom half of the image. It's not the turboGL because i tried it with TGL uninstalled and it did it anyways... I'm wondering if anyone had this kind of problems with their Dual-Head board and what's the workaround if there's one!

[impact]

On a G400, with the regular ICD Quake II worked fine for me, 1024x768x32bpp primary, pseudo 1024x768x32bpp on the TV. Just some minor tearing now and then, because I had vsync disabled. Maybe running in lower res would help.