Today I found whenever I use Chrome. My rMBP has A LOT of temperature spike, usually last for 10-15 seconds (65-75 degrees Celsius) ambient around 25 degree Celsius. Then I found Chrome uses GT650m instead of HD4000 in iStatmenus. Could this be the culprit? If yes. Any way I solve this? I tried Safari 6.0.3 and latest webkit. Both doing the same stuffs as Chrome did. Same website, same tabs. The temp never excess 55 degree Celsius. And I also notice whatever I browser on Safari. It only use HD4000, instead of triggering GT650m like Chrome did. Also in iStatmenus, I found both Chrome and Webkit utilize multicore. But I noticed Chrome use WAY more resource to do same thing Webkit does and in Chrome the UI performance even much less smooth than Webkit. I think this contribute to the temp spike as well. I tested both with charger plugged in and battery only. Same result. Also made sure "automatic graphics switching" checked in Energy Saver I know I can always uninstall Chrome and use Webkit. But few things made me not doing so. 1. Extensions - I have some work related extensions have no replace in Safari or at least not as efficient 2. Chrome sync everything with my PC, Mobile phone which is very convenient for me. So If possible, I want to stick with Chrome. annoyed by the UI performance but not annoyed enough to ditch Chrome. However the temp does. I use my laptop on my laptop quite often. heat would be a really big concern to me. Summer is coming here. Sorry for the wall of text and poor grammar(English is not my native tongue) Thanks in advance to anyone that can help or contribute.