You can run 40GB, but dual-channel gets weird.

Yes, you can slap a 32GB stick in that slot. Most modern laptops with soldered + replaceable memory support asymmetrical configurations like 8+32.

But dual-channel won’t work the way you expect. Intel calls it “Flex Mode” — the first 8GB on each stick run in dual-channel, leaving the remaining 24GB on the 32GB stick running single-channel. So you get partial dual-channel, not full.

That means memory-intensive tasks (like gaming or video editing) won’t hit peak bandwidth, but for normal work or multitasking, you probably won’t notice. If you really care about memory speed, match the replaceable stick to the soldered size (another 8GB). But if you need the capacity more than the speed, 40GB is fine.