Here’s the Image-Line videos about audio meters and performance:

• Image-Line’s article on Optimizing FL Studio performance
• Image-Line’s FL Studio Optimization YouTube Playlist
• Best Computer for FL Studio Article

Also, here’s my personal audio interface.  It’s been a huge upgrade from Focusrite’s first generation – Make sure it’s 2nd Gen:

• Focusrite Scarlett 2i2 (2nd Generation)