How do I confirm my motherboard supports dual-channel memory?

Check the motherboard manual’s memory layout section for which slots to use (usually A2 and B2 or same-colored slots). If you lost the manual, look at the motherboard itself — DIMM slots are almost always color-coded (e.g., two gray, two black), so populate the same color first. You can also verify with CPU-Z’s Memory tab, but if you put two sticks in the correct slots, it just works.