What is the easiest way to check if my RAM is running in dual-channel mode?

Use CPU-Z — it’s free and lightweight. Install the second stick, boot up, open CPU-Z, click the “Memory” tab, and look for “Channel #”. If it says “Dual”, you’re good. Windows Task Manager also works but isn’t always perfectly reliable. Most laptops with two physical RAM slots support dual-channel automatically if both sticks match in capacity, speed, and brand.