[idvusers] JAVA memory limit

Until recently I've used IDV with a max java memory of 1512mb. 
In one of the recent updates of IDV 2.7b2 (about a month ago) IDV failed
to start, until I reduced the max memory form 1512 to 1304mb
(jre\bin\java -Xmx1304m -Didv.enableStereo=false -jar idv.jar %*).
Trying to reinstall previouse versions of IDV did not help, so I guess
that there was some update to java. 
Does anyone know how to overcome this issue?
Also, is there no way to get beyond 1.5GB for java? 
I'm using Win XP SP2.
Ilan Levy