You can stream in Standard Definition (SD) comfortably. However, High Definition (HD) or 4K will likely buffer, as HD typically requires at least 5–25 Mbps for a smooth experience.
If you have just run a test and seen "3.7," here is what it means for your daily usage: Internet Speed Test 3.7
If you suspect 3.7 Mbps is lower than what you are paying for, follow these steps to get a definitive reading: You can stream in Standard Definition (SD) comfortably