It'll be a bit faster, but that has everything to do with the processor, and absolutely nothing to do with the RAM. I can't understand why people don't get this!!!
Cause you're wrong? I.E, with 512MB, safari wont have to reload pages until a much higher tab count, hence faster due to more RAM. Apps can have more stuff in RAM, hence they can browse larger dataset before coming to a crawl. Things get faster, cause they don't have to unload and reload due to memory limits.