Get the second stick. Dual-channel is worth it.

Yes, it will noticeably improve video rendering.

Dual-channel mode roughly doubles memory bandwidth, and video encoding is often bandwidth-hungry. You might see renders finish 10–20% faster depending on your codec and CPU, which adds up fast on long projects. Plus, going from 8GB to 16GB means you’ll stop hitting swap when the timeline gets heavy.

If your motherboard supports it and you match the stick (same speed, timings, voltage), it’s a no-brainer upgrade. Single-channel is leaving performance on the table.

Future you will thank you when renders finish faster.