Yes, you will be able to edit with that amount of RAM.
I currently have a pentium 4 2.5ghz processor and 512mb of rd-ram
is 512 enough to even consider editing a movie file that is 30-40 minutes long? i know the sony site says 512 is recommended, but it sounds very low to me.
Unless you wanted an excuse to buy stuff for your computer. In that case: Go out and get another 512, it will be impossible if you don't.