Hearing some fan noise, I immediately checked htop to see if any process is hogging the CPU. Nothing looked alarming, but turning off GDrive lowered CPU usage. I am not sure what the root cause is.
Chrome 1.0 on Windows had a similar annoyance - it was pretty fast for a 1.0 browser, but was absolutely not a refined product, using amazing amounts of memory and spiking my processor way too often.