That's funny, I've even moved a 1.2GB directory on a FAT32 drive on a P200 with just 32MB ram before, it took just 3 seconds (with very little disk activity). To Windows or any OS moving a file around a disk or renaming it are the same operation. In Linux you use the same command, in Windows/DOS the commands are different but internally they call the same function. I remember when I programmed in DOS assembly move & rename were the same call. This is only true if the file is in the same partition or file system, to move it from one to another it is copied first and then deleted form the source.
I would imagine that what's happened here is a case of lack of free memory and the dreaded swap file in action or a lack of disk space or severe fragmentation of the drive.
When was the last time you defragmented your hard drive?
By the way, boot into same mode and turn your screen saver of before you do this.