Media Player Classic in the K-Lite Codec Pack has a setting called "Store settings to .ini file".
MAKE SURE THAT OPTION IS UNCHECKED.
Media Player Classic still remembers your settings, it just stops copying them into an .ini file as a 2nd source. Having this option checked gives MPC 2-3 seconds of CPU delay during the opening and closing processes of the application.
Here's a screenshot of which option to uncheck:
I'm soo happy that MPC is flashing open and closed again, and I hope this tip helps many others out.
I believe the "save to .ini" setting is for the advanced users who want to modify settings within notepad, share their settings, etc. It's not good to leave on all the time obviously, because it causes MPC to delay on even the fastest of CPUs when you open and close it.