CVar gxTextureCacheSize

This CVar only works with gxApi being set to "d3d9"
This CVar controls how much of your graphics card's onboard memory is allocated to textures in-game.

Default Setting

 * 0 :Allows the client to set the cache size

Changing this setting
This CVar requires a game engine restart to go into effect. In-game, type the following /console gxTextureCacheSize setting Do NOT Alt-F4 out of wow or this CVar will not be applied when you load WoW again.

Alternatively, you can exit wow, open the Config.wtf file, and add the following line: SET gxTextureCacheSize setting