each GPU has 512MB of memory so there's 1GB physically, but it works the same as having 2 x 3870's in crossfire i.e. there will be two copies of the textures etc; one for each set of 512MB VRAM, for each GPU.
each GPU has 512MB of memory so there's 1GB physically, but it works the same as having 2 x 3870's in crossfire i.e. there will be two copies of the textures etc; one for each set of 512MB VRAM, for each GPU.