/-----------\
| 1 3 |
| 2 4 |
+-----------/
(top view)
When used in constant temperature, the original oscillator and TCXO provide comparable performance (+/- 0.1 ppm over several hours).
However, increasing the temperature from 28 to 48 °C means 0.14 ppm drift of the TCXO, but 3 ppm drift of the original oscillator.