I use CCleaner and Sysinternals' Autoruns to a certain extent. However much of the heavy lifting when it comes to system optimization, I do mostly all manually. I have a difficult time putting full trust into system optimization tools and particularly anything that modifies the registry.
CCleaner. Support for more cleaning routines are available with the additional Winapp2.ini, which is available there: http://www.winapp2.com/
CCleaner (mainly for browser) + Wise Care (for the rest), and some Windows commands. From mentioned software, I trust only Glary, but it does not find anything after the duo. I defrag booting Win USB and running it from CMD, it consolidates free space too. I also use TCP Optimizer to polish network settings and Autoruns for checking.
CCleaner set properly--learned my lesson the hard way with the registry cleaner, now use it very sparingly with a back up in place. Also run Windows Automatic Maintenance weekly, plus my own know-how to eliminate dross on my system.
Ccleaner (for daily cleaning of useful files) or Wise Disk Cleaner (for Windows Update cleaning), otherwise i do all tweaks manually.
All system optimization done on my machine is done so through the built in tools or manual tweaks. Example: It is not so common knowledge that windows built in defrag has limitations, mostly based on file size, unless one is aware how to run it via command prompt, and defrag all file sizes, free space ect.
i try to do this manually: i found a lot of threads/articles on the net that using this kind of tools is very risky. cu and greets from germany! Xone
Define, "Optimization Software". (Sic) I use CCleaner to remove temp files etc, but Process Lasso "optimises" my machines.
I use several programs. Advanced SystemCare Pro AVG PC TuneUp Avira System Speedup Clean Master for PC - It's very good at cleaning junk, but the registry cleaner has very minor issues with false positives, so I use it with care. Kerish Doctor System Mechanic - The Program Accelerator can make a big difference in performance if you have a hard drive. Other than it is unremarkable. I only paid for Avira System Speedup, and AVG PC TuneUp. Clean Master is free and the rest I got as giveaways.
Ccleaner and Wise Care, essentially for cleaning. Basically I don't believe in more complex optimization softwares: I think that the better thing is to optimize the system working personally on the actives services, used processes, startup programs.... Anyway Wise Care can help to do it.
Besides others (e.g. CCleaner) - using here Puran Utilities that has many useful and reliable tools like: Puran Defrag | Puran Wipe Disk | Puran File Recovery | Puran Registry Defrag | Puran Registry Cleaner.