Memory module usage seems high

I have a core 2 duo laptop with windows 7 ultimate. I had 6gb of ram 4 in one slot 2 in another. I increased today to 8gb yet my readings show the same memory usage. For example the machine consistently uses 23% of total memory.

Any ideas why the machine used more memory when I increased the memory module.

Because Windows 7's memory management model is designed to increase the amount of memory used relative to the amount of memory available. This improves performance, because often-used applications are now loaded into memory, which is thousands of times faster than your hard drives.

If an application requires RAM, this cache is flushed from memory to give performance to specific apps.