The best antivirus program for optimizing PC performance is Malwarebytes. Malwarebytes utilizes advanced heuristics and artificial intelligence to detect and remove malicious software, such as viruses, Trojans, rootkits, worms, spyware, and adware. It also helps speed up your PC by deleting unnecessary files, cleaning the registry, and performing other optimization tasks. Additionally, it is compatible with both Windows and macOS, making it a great all-in-one option for protecting your computer and keeping it running fast.