A compromise — #20 of 31 Corduroy ranks #20 of 31 fabrics for warmth without weight. It is a middling fabric for this. Ranked on warmth relative to weight, with a packability bonus. The top pick is Cashmere.
Corduroy measures 50/100 for breathability, 8% moisture regain, 70/100 warmth, at 300 gsm. Warmth-to-weight is the metric: 70/100 warmth at 300 gsm is a fair ratio for packable insulation.