can not start eclipse.exe with Xmx1024m in my 2GB RAM PC

[taotao_haha]

hi,
I got a problem with starting my eclipse.
my RAM is 2GM
but when I set -Xmx1024m in exlipse.ini, it comes the error of
[JVM terminated Exit code=-1]
( It is ok when I set -Xmx512m)

and I searched a lot
I even changed boot.ini with /3GB option.

my PC is windows xp professional 2002 with SP2
the following is my eclipse.ini setting

-showsplash
org.eclipse.platform
-framework
plugins\org.eclipse.osgi_3.4.0.v20080605-1900.jar
-vmargs
-Xms256m
-Xmx1024m
-XXPermSize=256m
-XXMaxPermSize=512m

help me please!