Windows is not seeing all memory

You want to make sure that the memory is installed in pairs. Try putting in a single memory stick and see if the memory is being properly reported. Make certain that the memory (RAM) is compatible with the motherboard and is properly seated. Also make sure both sticks are from the same manufacturer

Dual Channel RAM

You’ll need two RAM sticks to get dual channel. It works like RAID for memory, and you’ll get a speed boost. However, you probably won’t notice a difference. Your system will probably experience a 5 percent performance boost. You need to improve performance at least 10 percent to see a difference.

To really see a significant difference, add more memory or get a faster hard drive.