I recently upgraded to ableton 10 and a new laptop, the latency and CPU are down, but I was getting odd spikes when I sent midi messages from a pedal. On further googling, I found that the default windows power setting is “balanced”. I changed it to “high performance” and the CPU dropped yet further, from 30% to 10%. Result! It probably means I will have reduced battery life, but I try to plug in the power whenever possible, so it’s not a serious issue. I used this article to tweak the settings.