BHUMR-C comes with the Linux 3.13.0-39-generic kernel and nVidia-331 display driver. This is the default kernel in the Ubuntu 14.04 LTS mini/net-install system on which BHUMR-C is based. On my build system, I have to run the proprietary display driver otherwise Cinnamon runs in software rendering mode with the Open Source Nouveau display driver.
When building BHUMR-C, I experimented with the 3.17 Linux kernel and the nVidia-340 display driver. This combination of kernel and driver caused Cinnamon to run in fallback mode. I am currently testing it with the 3.16 Linux kernel, and have not encountered any issues.
So what I'm saying is: DO NOT ATTEMPT TO RUN THE 3.17 KERNEL IN BHUMR-C. It won't work. I know it won't work. Honestly, unless you know you need a certain kernel to get specific functionality out of your hardware, I'd recommend against running any kernel other than what ships by default. If you do, you risk BORKING your system. If you do, don't blame me.