Jenkins 2.5 version seems to run with high memory pressure very often.
Am running jenkins with 2.5 version with jdk1.8.0_25 in windows environment, initial heap is set 128MB and Max set to 3072MB. Very often, Jenkins UI page will become unresponsive, it seems to suffer memory pressure. After Performing GC many times, Jenkins seems to become normal. Any fix to overcome this problem?
There is not enough information to investigate further. It will be interesting if you are able to share thread dump.
Current Jenkins LTS is 2.7.4, I recommend to upgrade to latest LTS, as there are lot of fixes, and could resolve your issue.