Hello all, I have this MacBook pre-unibody, fitted with a 120GB SSD and 4GB RAM. Currrently running El Capitan (incrementally updated from the first public beta), I find it rather sluggish and annoyingly loud, regularly over 80 degrees without 100% CPU, at times going over 100 degrees under full load (measured with Macs Fan Control on the CPU diode). Thermal paste isn't the issue (Gelid), radiator is clean. Is OS X prevently spinning the fan faster as load increases, without waiting for the temp to actually be higher? At first I thought about drilling so-called "speed holes" like the ones here, but before resorting to extreme measures that will surely increase dust intake, I thought it may simply be running a too recent Mac OS X for its age. Hence my question: what would be the best Mac OS X to run on this older MacBook, which works fine otherwise? The choice would be between still-supported (AFAIK) Mac OS X versions. 10.9 Mavericks? 10.10 Yosemite? 10.11 El Capitan, but a fresh installation / restore documents from TM backup? 10.12 beta?