CS-Nation

Covering the future of Counter-Strike
do skins affect system performance in cs?
Custom skins vary in quality and complexity; those with more details (a larger number of polygons and faces) will take longer to load, and may detract from your performance when playing, depending primarily on the speed of your computer and the available RAM and your graphics card.

If performance is an issue for you, you may want to stick with the default skins and models.