During most work days, I have dozens of tabs open, and Chrome can start to feel a bit sluggish under the weight of my hunt for helpful tips and tricks and, this time of year, Cincinnati Reds news among other distractions. With TabMemFree, Chrome unloads inactive tabs so they don't take up CPU and memory resources.
After installing TabMemFree, a small button gets added to Chrome's toolbar. Right-click on it and select Options. There are only two settings to tweak: Timeout and Tick. For the first, set the number of minutes you'd like TabMemFree to wait before it forwards a tab to a blank page to upload it from your system memory. The Tick setting sets the interval for when TabMemFree checks for inactive tabs. Lastly, you can turn the extension on and off by simply clicking on the button (TabMemFree is on when the three arrows appear about the little black rectangle).
In my testing, I found TabMemFree to be inconsistent. In fact, the developer states in the description in the Chrome Web Store, "WARNING: Unstable at this moment, don't use it if you have important tabs." In my experience, it would park only some of my open, inactive tabs, and do so on a schedule that seemed to vary from the Timeout setting I had selected. Also, there is no way in the settings to white-list Web sites so their tabs remain open and active, though I would settle for it parking all of my open tabs instead of a seemingly random selection.
Further, when TabMemFree forwards the tab to a blank page, you lose the favicon and title of the Web page listed in the tab. In their place, you get the TabMemFree favicon and title "chrome-extension," forcing you to remember which unloaded tab is which. To revive a tab, simply click on the tab and the page reloads. You will lose your spot, however, if you were in the middle of a YouTube video or another media file.
For Chrome users who acquire dozens of tabs throughout the day, TabMemFee is worth investigating. For the rest of us, it's probably worth waiting for the developer to make the extension more stable and feature-rich.
According to the developer, BarTab for Firefox inspired TabMemFree for Chrome. Unfortunately, BarTab is no longer being supported and does not work with the current version of Firefox. Take a look at Seth Rosenblatt's video about how to speed up Firefox with a BarTab-inspired tweak.