I have an Asus EAH2600PRO 512mb on a media pc connected to a TV with HDMI cable. I recently discovered that the OS (Xubuntu 13.04) recognize it as 256mb only GPU.

The gart.size setting is set by default to 512 as it should.

The display is a 1080p one so i really need those extra MB of RAM on this old GPU in this resolution.

Why is this happening and what should i do to make the OS recognize it as 512mb GPU?

Thank you.