Gem and texture size

[umläute]

i have noticed some times ago, that when i use a huge number of sperate
textures, at a specifique point the CPU-load increases by numbers --
this is, of course, due to the lack of memory of my grafx-card

but::
since i only used few *different* texture-images (par example: only 1
single image, that is textured on let's say 128 geos), i guess there
could be a way to tell the grafx-card to reserve memory only for one (or
"few") image(s). so there would be no need to access the "slow" main
memory.
How ?

mfg.fasd.ar
hannes