Last week the Linux Mint project launched a new version of the Cinnamon desktop environment. Cinnamon uses GNOME 3 technology to create a classic desktop environment, similar in look and feel to the legacy GNOME 2 environment. The Cinnamon developers have been working hard to make their desktop environment faster and more reliable. "A huge amount of work was done to review the CPU usage in various parts of Cinnamon and many improvements were made. Performance was gained by optimizing how Cinnamon reacts to particular events and reducing the number of tasks or repeated tasks it performs. The menu, for instance, is refreshed about 6 times as less as before... signals resulting from connecting a USB device are grouped together and lead to 1 action, reducing 4 concurrent reactions into a single one." Multiple panel configurations and multiple monitor support have been improved and the file manager now performs operations in sequence rather than in parallel. The new file manager behaviour avoids swamping the computer's processor and disk with file operations. Cinnamon 2.6 is already available to Linux Mint Debian Edition users and will appear in the upcoming release of Linux Mint 17.2
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And in regards to v 2.6, here's a bit of news on that front:

2 Jun 2015

On behalf of the team and all the developers who contributed to this build, I am proud to announce the release of Cinnamon 2.6!

This new version will be featured in Linux Mint 17.2 “Rafaela” planned for the end of June and in LMDE 2 “Betsy”
Cinnamon 2.6 ← Segfault

A few changes/additions I've noted while quickly scrolling and reading through the above link available for your reading pleasure.