You mentioned that "the Full GC's getting triggered every one hour, its getting triggered every 1 minute. "
Which is an indication that the Heap Dump needs to be investigated be investigated.
Also why do you think that the frequent GC is being caused because of the mentioned parameters ? (-Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000)
If the Full GC is happening too frequently then either the heap is getting filled too frequently which is an indication of high load, which is leading too many objects creation OR the Heap is not tuned properly. Analyzing the Heap dump to see which kind of objects are occupying more heap space will give some idea.
Also -XX:+PrintTenuringDistribution JVM option will help in understanding the age distribution in the new generation.
EAP 4 and EAP6 are not comparable.
In general you should start with the default settings and only adjust Heap size. Also you should enable the gc logging (for later EAP6 versions this s done by default)
Also I would use the latest Java7 version for EAP6.