16GB total support means 16GB total.

Yes, you can. If the motherboard says “up to 16GB,” two 8GB sticks get you exactly that. No overshoot, no problem.

The real check isn’t the total — it’s whether the board actually supports 8GB per slot. Most boards from the DDR3/DDR4 era do, but some cheap or older ones cap each slot at 4GB or 2GB. Look up the manual or the spec sheet on the manufacturer’s site. Also double-check the RAM generation (DDR3 vs DDR4) and speed rating — mismatched RAM won’t work or will run slower.

You’ll be fine 99% of the time. Just don’t trust the sticker on the slot alone.