Memory Usage

[abovelegit]

so when I turn on my diamond, after TF3D is launched the memory usage stays around 33% but after launching some apps obviously it goes higher, but when I close them the memory usage doesn't revert back to 33% instead it stays higher like at 47% any ideas on why this is or if there are any tweaks to prevent it? by the way im running juicys 2.4.