If it is just for emu and online flash style games. You would be better off with more CPU than memory if you are trying to keep costs low. I can not think of a single game in MAME that needs even 16GB (not saying it doesnt exist just I can not think of any). 8 would probably suit you fine. I only have that much because I run VMs a lot. Just make sure you get something that is dual channel to keep the perf up. You may want to check the benchmarks but AMD is usually better on the desktop range these days. There is a pretty good range of stuff on that site so you would have to be a bit more specific on what you are looking for and thinking and your price range to get a better recommendation.