Kibana 7.6.0 With ECK has high cpu usage

We used to run Kibnana 6.2 with the offical Docker-Image and had a systemload of about 0.2 for the two containers we used. Recently we switched to ECK and Kibana 7.6 and the load of the container is between 0.5 and 2.3. We used the same resources as before. Loading times are fare worese than with the old container.

    cpu: 300m
    memory: 1500Mi
    cpu: 100m
    memory: 1500Mi


Is there some drastic change between this versions ? (I know 6.2 is rather old but the load increase should not be that high or does it?)

Even with more resources response times are all over the place: