Recently, Chrome started really dragging on my Mac. I opened up the Activity Monitor and figured out that it was Adobe Flash that was taking up all my CPU time. If you're having this issue, try installing the FlashControl extension for Google Chrome.
From the FlashControl extension page:
FlashControl automatically blocks Flash content and then lets you choose what to load. It helps avoid annoyances and can overall improve your browsing experience.
Replace Flash content with placeholders. When you want to see content, just click a placeholder. Free up memory and CPU with additional re-block features; block per element and during idle time. Use the blacklist to avoid unwanted content, or the whitelist to allow your favorite sites.