Macbook Pro Late 2011, Mavericks 10.9.5 had my RAM consumed up to 2.75 GB (out of 4.00 GB) with no apps running except Finder. Hard Disk Storage: ~300 GB free out of 500 GB
Creating new, renaming, and/or deleting folders with Finder made it lag and had to load ~1 min before it did the process. This is very disturbing and distracting, even opening a Word document takes ages.
Activity Monitor Screenshot (Only Finder and Activity Monitor running):
I just had my Hard Disk cleaned and Re-Installed Mavericks recently, but there were no issues with previous experience of Mavericks. CPU is 70% idle.