Hi Aleksandr,
You might want to determine the origin of the ad that is causing the drop of fps and speak with the corresponding ad network for that issue. Generally, though, animated ads tend to incur some performance overhead due to the CSS and JS happening under the hood. On older devices where the specs might not be as powerful, frame rate drop can happen.
Try building from scratch with only our ad SDK, then start adding the other ad networks and logic until you notice the performance bottleneck.
Vu Chau
Mobile Ads SDK Team