Iolo System MechanicShow
Download [here]Iolo System Mechanic removes junk files and unwanted apps, blocks bloatware and unwanted auto-run settings, clears out RAM and wipes various logs, browser histories and caches.
Piriform CCleanerShow
Download [here]Piriform CCleaner has been around for a long time, and part of the reason for its ongoing popularity is that it cleans the parts of your PC that many other free system optimization tools don't.
There's a paid-for version of the optimization toolkit that adds real time protection and cleanup scheduling, but the free edition of CCleaner covers the important stuff such as removing temporary files, getting rid of browser caches, removing unwanted cookies while keeping the useful ones and so on.
Razer CortexShow
Download [here]If your system struggles when you're trying to get your game on, Razer Cortex could well be the answer. This free PC optimization software suspends unnecessary system processes, clears out memory and defrags your system to get the very best game performance possible.
Razer Cortex is available for Windows 7, 8 and 10, and while the differences won't make you jump up and down in astonishment - for most people the results will mean slightly smoother visuals rather than astonishing performance improvements - it does automate the fiddly process of turning off unnecessary software and services when it's time to play.