I was reading this review and he said there could be more RAM since the Mini supports Siri and the iPad 2 does not.
"Its dual-core A5 chip might be the same as in the $399/£329 iPad 2 (introduced in 2011 and still on sale) although it's possible Apple added more RAM, since the iPad mini supports Siri, and the iPad 2 (which has 512MB of RAM) doesn't."
"Its dual-core A5 chip might be the same as in the $399/£329 iPad 2 (introduced in 2011 and still on sale) although it's possible Apple added more RAM, since the iPad mini supports Siri, and the iPad 2 (which has 512MB of RAM) doesn't."