Hi,
I have 13" MBP (2011) MacBookPro8,1 that runs OSx 10.10.5 Yosemite. I have 16GB Ram and at least 200GB free hard drive space.
Since a fair couple of months now, the CPU tend to spike to over 200-300% when using for example Lightroom or even Firefox. It is like it's not multitasking/swapping...