Response times and performance
All Digital Recommendations data that is accessed through dynamic recommendations is delivered using a Content Delivery Network (CDN).
When recommendations are requested for each item, the first request of the day can take up to 400® milliseconds to complete the full round trip because this data is at the CDN origin. Each subsequent response is delivered from cache at the edge where response times averages 20 milliseconds. Therefore, the typical response time for performance planning purposes is 20 milliseconds. These response times are derived from a testing environment using a lightweight HTML page which is not burdened by the heavy code requirements of a typical merchandise site. Therefore, your actual experience might be different based on the design of your page. One key step for fast response times is to place the cmDisplayRecs function immediately after all recommendation request functions are called.
Test before launch
Before you go into production, test these changes as you would any release of code changes to your production website. As part of this test cycle, the test recommendations in the most common browsers.