How are textures stored in VRAM?

[Liaen]

Hi there,

 

I've got a question regarding textures. If I compress a .dds texture with DXT, it takes up less space on my hdd.

But when I play the game then and the texture gets loaded in my graphics cards VRAM, does it get uncompressed or does it stay compressed?

 

Lets say I have an armor texture 2048x2048. Uncompressed its 16MB in size, compressed with DXT its 2.7MB.

Does this texture take up 16MB of my VRAM or only 2.7MB? So is texture compression only good for my HDD or also for my VRAM?

 

I'm playing around with Textures Optimizer and the official HighResTexturePack and I'm wondering if I should keep the 2k textures if I can compress them or if I should resize them to 1K.