Will it overburden the browser if ExtJS3.4 and ExtJS4 are both used in an application but in different browser windows?

Question

I have a web application in ExtJS 3.4. Now on click of a button I am going to open a new html window.I am planning to go with ExtJS 4 in that new html window. But few Questions which I need to answer are :

1. Will it be heavy on browser ? IF yes How much ? (Is it almost of ext-all.js and all these library files and the files which I include in both html pages?)
2. I heard that ExtJS 4 has garbage collector So will it be better to go with ExtJS 4 ? Because Everytime they click this button (which is in ExtJS 3.4) a new window will get opened in which will load Extjs 4. So when they close garbage collector will take care.

So at last whether to use ExtJS 3.4 only in that new window or ExtJS 4 ? why ?

For reference : All the files loaded to browser sita in below path: C:\Users\"User Name"\AppData\Local\Microsoft\Windows\Temporary Internet Files

Answer 1

No, it will not be too much for the browser (on any fairly modern computer that is), and there is no reason why it should be. The garbage collector in ExtJS4 will only be useful if you use asynchronous loading of files. It has nothing to do with overall performance. Also note, that it some browsers (most notably Chrome) each window/tab is run as a separate process, so that they do not influence each other.