2.23 should be better with that device. The Intel driver installer from the prior instructions actually only updated the Intel kernel driver to Linux 3.16 version. As of ubermix 2.2, the 3.16 kernel is the default.
All that said, I have built a backport package for the Intel kernel driver from the 3.19 kernel that you can download from here:
https://drive.google.com/file/d/0B52M_cKAX2ARREJiZWl0c0FoUjA/view?usp=sharing . On the B115s, I'm seeing better performance and improved battery life with the newer driver. Should work on all Intel laptops, and I plan to include it as a default in a future build, once I've been able to test it a little more.
You might also try updating the user-space (ie xorg server) drivers, which include a lot of the 3D code, to see if you can eek out a little more performance. There is some risk in that these are typically nightly builds of upstream updates, so you'll want to be sure to test them fully before you deploy at scale. To install, do the following from the terminal (ctrl-alt-t) - preferably in generic mode:
sudo add-apt-repository ppa:oibaf/graphics-drivers
sudo apt-get update && sudo apt-get dist-upgrade
I haven't seen a huge difference in performance myself - your mileage may vary.