The performance difference between dual channel and flex channel is minimal at about 2% FPS reduction when playing games. But the cost difference is about Rs 1300. If one doesn’t need 16GB RAM, then installing 8+4 = 12GB RAM is enough and one doesn’t have to fear loss of dual channel and save some money in the process.
https://www.amazon.com/Crucial-PC4-19200-SODIMM-260-Pin-Memory/dp/B01BIWMWVS

