Unity memory run out issue

Hi, I am using Unity 2.6, seems it has serious memory issue. As I observed, it will use all memory system has, in my win7 64bit, it's normal my Editor or webplayer take more than 1.2GB virtual memory. In 32 bit XP, it gets less but still up the the limit. Then the problem is, my browser will crash after it takes so much memory.. Is this issue fixed in future unity version or not?

Another memory issue about asset bundle. Same project, if I do every level in local(not as assetbundle), the max memory it takes about 1.2 GB. But, if I make single levels into .unid3d file and download it runtimely from server then load the level, the max memory taken is 1.6GB. What happened here? Is there will be so much difference if I make level into one full bianry or seperate them into standalone .unity3d files?

Thanks a lot for help me out here