of course depends on comparroson eg 16xAA vs 50% more pixels
but 4x pixels vs 4xAA
Give me the pixels all the way
iphone 3 & 480x320 & 4xAA
vs
iphone 4 & 960x640 & 1xAA
which one you gonna choose?
It would be one hell of a case where there would be any significant performance cost on a iPad4 or even iPad3 for 4x Multisampling even in 960*640.
The iPad4 loses in GL2.5 (which is quite a demanding case compared to today's mobile games) around 12% of performance in 2048*1536: http://www.glbenchmark.com/phonedetails.jsp?benchmark=glpro25&D=Apple+iPad+4. while the iPad3 barely 7% (probably because there's a bigger bottleneck elsewhere): http://www.glbenchmark.com/phonedetails.jsp?benchmark=glpro25&D=Apple+iPad+3
While a large crop of games on those two aren't actually rendered in their native resolution, are there any games that scale as low as 960*640?
What you can do however on an alternative SFF mobile device like the Galaxy S3 if you have fillrate to spare to enable 16xAA, which is a combination of 4xMSAA + 4xSSAA.