We just finished upgrading to V10 and I'm experiencing some seriously slow page loads. We're talking ~5-7 seconds before the page loads. It's especially bad on the Shoppingcart page. It takes close to 10 seconds to register the shipping method that was selected. This delay is causing major headaches with my customers with the long time it takes to complete an order.
Here's a webpagetest.org test result showing the long time to first byte - https://www.webpagetest.org/result/170127_ZD_14T7/
Any help or ideas are appreciated.