Have a look at this image:
Look at "soffice.bin" and "soffice.exe."
soffice.bin is the OpenOffice backend that
must be opened in order to use any OpenOffice program. OpenOffice comes with a QuickStarter program that keeps this
forty-five megabyte program open in the background to make starting up individual applications faster. That's 45 MB, plus 2-4 MB for the Calc application,
before any files at all are loaded.
Microsoft Office has no such background program. See the Excel.exe? That's with the same spreadsheet open (which Excel opens just about instantly, but Calc takes 2-3 seconds to open), and it's under 14 MB.
On a fresh install on a modern system, Excel opens up in under a second. OpenOffice, without the 50+ MB file already loaded by QuickStarter, takes 3-7 seconds to load.
OpenOffice is,
and always has been more memory intensive and slower to start than Office.
You are mistaken if you believe that Writer is using only 4 MB. This is impossible, because OpenOffice
absolutely requires the loading of this soffice.bin file.
But don't take my word for it.
"As you can see, OpenOffice.org takes up a lot more RAM to load than Microsoft Office applications."
"As you can see, OpenOffice.org and XML in general is extremely slow compared to the native Microsoft XLS binary file format."
http://blogs.zdnet.com/Ou/?p=119
"Calc took almost a full minute to open the spreadsheet, while Excel handled it in a few seconds. Also, upon closing the file, Calc froze. This crash was recreated a second time. Excel did not have any issues closing the same file."
http://www.crn.com/software/206903560
"However, the key problem it's continually faced has been one of compatibility, particularly with its Microsoft rival, and the problems do still exist here to an extent."
"the main problem was that it took OpenOffice a little longer to work its way around it than the Microsoft application."
http://www.itreviews.co.uk/software/s607.htm
So, yes, OpenOffice is a good program. I've installed it on many clients' machines, even office environments. But don't make the mistake of thinking it's
better than Microsoft Office. It's an incomplete clone, pure and simple.