Drain on Server CPU

I have an issue regarding the drain on my server cpu being caused by socialads. The system reports back the number of clicks and impressions. However it appears it does checks for what appears to be data regarding the last time the advert was shown. My website is quite popular and can have 100s of visitors on line at the same time quite often. Some of the pages could have four or more adverts being served. As a result of this, my database now has over 6 million rows of data that appears to be checked every time a page is served. This is draining the resources and really slowing the website down substantially. Does anyone have any suggestions as to how I can address this.