Wha!? If Kaspersky slows your computer down, Norton or McAfee or the likes would virtually screech it to a halt
The best on I have found is System Suites. It cost $39 for three licenses and a year of updates. I have used it for 4 years without a problem. I used Norton because it came free on my lap top for 3 months and it sucked, I was glad to install my System Suites on. It also comes with great tools to keep your computer running smooth and easy one click ways to clean you temp files and otehr junk. It also has spyware.