quicker buffer transfers

[Possible speed improvement]

Ok, this is probably reasonably obviouse, but i thought
id post it anyway.

- If you are planning to transfer buffer data from an
- image buffer to a texture buffer - you should ensure
- that the texture buffer is loaded into gfx card mem [flag 256].

I tested this a long time ago + it seemed to have quite
a large impact on the speed of transfers..though i would
have thought that textures would be resident in video memory
by default...anyway, video mem to video mem blits are going
to a lot faster..

It may not make a difference on all systems..

interesting thanks

In fact this was the reason why Bit 256 was introduced.