I personally have an I5-2430 CPU with 8 GB of RAM. I run with 22 web sites, my Windows Live Mail, and Spider Solitaire, Wordpad, and occasionally Word and Windows Explorer open and am currently using only 49% of my RAM. It depends on what you're using the computer for though; video editing and complex games can take a lot more resource. I never have a slowdown since I upgraded from 4 to 8 GB, but I don't do video editing or play games more complex than spider solitaire. If you have too little RAM, you'll REALLY see slowdowns, but a too slow CPU can be a pain too. I rarely see my CPU get over 40% busy, but there are occasional spikes into the 80s and 90s.
What is more important for faster PC, RAM or CPU? I run a lot of applications at the same time and I would love to have a computer that runs smoothly without freezing. For this kind of use, is it good to have Intel i3 and 16 GB Ram or i7 and 4 to 8 GB RAM, both having SSD? What is more important for faster running PC?