setInterval effected by framerate?

I’m trying to do some setPixel() drawing at high speeds and I’m running into some weirdness with setInterval. I was under the impression that by setting a interval to run you were effectively running the function independent from the time line until the interval is cleared.

If i set the interval time to 10 or 1ms the function runs a different speeds depending on the framerate of the movie. Shouldn’t it just run as fast as possible regardless of the framerate? Any experience on this?

thanks!