Rancher server uses 1.2 GB memory?

After four weeks of uptime my rancher-server became very slow so I checked docker stats. It was constantly using 160% CPU and 1.4 GB of memory.

I upgraded to 1.1.0dev1 and now the CPU usage is constantly between 4% and 100% and its still sitting on a lofty 1.2 GB of memory.

What could be the cause for this problem?