I don't have information about someone playing CS:GO on an old Core 2 Quad.
Specs listed below. FPS remains consistent across conditions, including smoke.
Core Duo Q8600 (or similar models) ran smoothly at 240 frames per second with 4GB RAM, achieving 60-70 FPS on 1400x900 resolution.
It's a quad. What do you mean by "in smoke"?
the last time i played with that pc was two years back