I was so sure I was right that I tested it, and it turns out I'm not lol.
These are the results for drawing 1000 circles per step, for 10 seconds (precision set once per step).
So the results are:
1. draw a circle at precision 4 (0.17ms)
2. draw a circle at precision 24 (0.26ms) (Default setting)
3. draw a circle using a sprite (0.28ms)
4. draw a circle at precision 40 (0.30ms)
A circle at precision 4 is fastest but, a circle with 4 points is just a square at 45 degrees so, not particularly useful.
So in conclusion, although slower and uses up your texture page, drawing a circle using a sprite might achieve the effect you're looking for (depending how large the circle you need is). But I correct myself, it sadly won't be faster.