Use CPU-Z to confirm dual-channel, then stress test with Memtest86

Run CPU-Z and check the SPD tab—it shows each slot’s channel assignment. If both sticks (or soldered + SO-DIMM) show different channel numbers, you’re in dual-channel. Then run a full pass of Memtest86 to verify stability. That’s all you need.

Most modern laptops pair soldered RAM with one SO-DIMM slot. After adding a stick, open CPU-Z > Memory tab: look for “Channel #” next to “Dual” or “Single.” If it says Single, your channels are not working together. That usually means mismatched sizes or speeds. Dual-channel doesn’t have to be identical sticks, but it often requires matched capacity per channel (e.g., 8GB soldered + 8GB SO-DIMM works; 8GB + 16GB may fall back to single).

For the actual verification, Memtest86 (free version) runs from a USB and checks every address. Let it run at least one full cycle. Passmark’s MemTest86 is the standard. I’d also run a quick bandwidth test like AIDA64’s cache & memory benchmark—if your read/write speeds are roughly double what a single-channel system would