RAM upgrade for Acer Aspire One Happy intel atom N550 1.5 Ghz? (windows 7 starter 32 bit)?

You can upgrade to 4GB but 32 bit OS only supports around 3.5GB of RAM (More [maybe 3.6GB based on other's experience] or Less [3.2GB or so])

I doubt upgrading at least 1GB of RAM would make a whole lot of difference. I do not know what you're doing with the computer but if it's just general stuff like browsing,watching a YouTube video, or typing up documents then I suggest not upgrading the RAM. If you're looking to do heavier stuff then I suggest just getting a better computer. Your computer is a netbook after all. You won't do much past general stuff.

I have a similar system w/2gb ram running w7 w/sp1. it will help the processor run smoother, you will only see about 1.5gb ram running 32bit os. if they supported 64bit then maybe the full 2gb ram would be seen. you'll be able to run msoffice 7 or 10 too. you'll enjoy the increase as I do. I stream music, can burn dvd's & cd's, watch youtube, movies, & surf the net a lot with mine. hope this was helpful.

It will make startup time much much faster-speaking as someone who's done the 1GB to 2GB upgrade to an Aspire One N550

Should see some, but not much, since your processor is horrible.