When implemented in Si-Ge HBT technology, the differential Colpitts LC Voltage-Controlled Oscillator (VCO) can deliver low close-in phase noise by virtue of its low flicker noise corner frequency. The Armstrong topology reuses bias current and therefore should be more power-efficient than Colpitts. By comparing differential Colpitts and Armstrong architectures side-by-side, this paper shows that the Armstrong topology can deliver similar noise performance with an order of magnitude lower power consumption. This gives the Armstrong an 11 dB advantage in terms of Figure of Merit (FoM).