v5 is very very old and no longer supported.
Try v7 (free upgrade as always).
There is no way that JMR should be caching 2GB of data in memory. Something else is going on if you are seeing JMR using 2GB of memory. Memory management is handled by the core .NET subsystem (part of the OS now).
If you are still experiencing this with v7 then please give an example of a url hosting a video where this is occurring and a screenshot showing 2GB of memory usage by the jmrp.exe process. We can then go from there.
From CRS @ 28 Jul 2017 11:07