User blog comment:Hellogiggles/Computer help./@comment-26744861-20121115200352

TS3 isn't as demanding as one would think - you can actually run it on the highest settings with a smooth frame rate on an Intel HD GPU.

You can find the minimum system requirements on this page. Note that Vista and 7 (and probably 8 too) use the same specifications. I'd say by today's standards, 4GB of RAM is sufficient for everything to run smoothly though you can never have too much RAM (I'm using 6GB and I can run literally all of my games on the highest settings at ~60fps).

Hope this helps! :)