Which of my 2 iMac Computers is best for Pro Tools

I am new to this community so I hope this is the best place to ask my question.

I have 2 iMac computers and I have Pro Toos 8 on them both. I want to know which one would be the better computer to dedicate to my Pro Tools software and future upgrades.



21.5" mid 2011 iMac12,1 intel i5 2.5ghz Quad Core AMD Radeon HD 6750M 512MB OS X 10.8.5



OR



27" mid 2010 iMac11,3 intel i3 3.2ghz Dual Core ATI Radeon HD 5670 512MB

OS X 10.8.5



I am not computer savvy so any help would be greatly appreciated.



Thank you

Gary