If you are chasing optimal, lag-free performance that is ready to handle modern workloads, Dual Channel is the undisputed winner. However, going Single Channel isn't a sin. If your budget is tight and you can only afford a single, high-quality module like the ET ColorSync DDR4 16GB 3200MHz, go right ahead. It is much better to buy one reliable stick from a reputable brand than to force yourself into buying two cheap, low-tier sticks that might fail. Use it for now, save up, and grab its twin later to unlock the full power of Dual Channel performance.