Well there's two possibilities regarding the video memory (stuff gets moved about if it runs out of room and that texture map will make a big difference).
The other possibility though - have you checked that texture is actually appearing at that resultion? I have a similar thing on one of my really old PC's that it runs my waterworld project at high resolution faster than it does at low resolution - because the card isnt loading all the textures, and a mesh without a texture is much faster to render.
That's all I can think of at the moment...
The other possibility though - have you checked that texture is actually appearing at that resultion? I have a similar thing on one of my really old PC's that it runs my waterworld project at high resolution faster than it does at low resolution - because the card isnt loading all the textures, and a mesh without a texture is much faster to render.
That's all I can think of at the moment...