Lag with large brushes and files

Question

I typically work with large files around 10000 pixels, 300 dpi.  But I'm getting a lot of lag when I use brushes larger than 1000 px as well as a long wait to open and save the files.
Is this a RAM issue?
Here are my specs:
OS Name             Microsoft Windows 7 Home Premium
Version 6.1.7601 Service Pack 1 Build 7601
System Manufacturer      Alienware
System Model    M18xR1
System Type       x64-based PC
Processor            Intel(R) Core(TM) i7-2630QM CPU @ 2.00GHz, 2001 Mhz, 4 Core(s), 8 Logical Processor(s)
Installed Physical Memory (RAM)               8.00 GB
Total Physical Memory    7.98 GB
Available Physical Memory            4.43 GB
Total Virtual Memory      16.0 GB
Available Virtual Memory              11.2 GB
Page File Space  7.98 GB
And two GPUs: NIVIDIA Geforce GTX 460m
I'm upgrading my RAM and GPU soon anyway but wanted to check and make sure it wasnt some other underlying problem?

Answer 1

I'm having some trouble deciphering what is going on here. I'm useing Paul Tuersley's response as a starting point. Here is my modification not that it matters since it isn't working at the moment. I don't actually know what some of the script is doing. Right now "theFiles" is returning all of the files that are not real files, folders and .DS_Store when I want it to be an array of all of the files in the folder.
Could you help me break it down?
// Log the selected footage
var selectedFiles = app.project.selection;
// Choose the folder to scan
var theFolder = Folder.selectDialog("Please select folder.");
if(theFolder != null){
    var resultArray = new Array();
    folderFiles = checkForFiles(theFolder, "");
    $.writeln(resultArray.toString().replace(new RegExp(",", "g"), ""));
    // Compare selected files to files in the folder
    for (var i = 0; i < selectedFiles.length; i++){
        compareFiles (selectedFiles[i], folderFiles);
function compareFiles(file, folderFiles) {
          for (var i = 0; i < folderFiles.length; i++){
                         if (folderFiles[i].name==file.name) {
                                        alert(folderFiles[i].name + " and " + file.name + " match!");
function checkForFiles(folderItem, tabString) {
    var theFiles = folderItem.getFiles();
    for(var c = 0; c < theFiles.length; c++){
        resultArray.push(tabString + theFiles[c].name + "\r");
        if (theFiles[c] instanceof Folder) {
            checkForFiles(theFiles[c], tabString + "\t");
    return(theFiles);