Is this good enough for DayZ

It will run it very well. However with object detail at high and ATOC on grass it runs like arse. I get to around 10fps in places with a GTX 660 with all settings maxed out. However I can easily get a constant 60fps with a few settings turned down and frankly it looks only slightly less good.

hey i just bought a mac pro just the standard one. im gonna run bootcamp and install windows 7 but i was wondering is this computer good enough for dayz to run?

Without any specs I have no idea.

2.5GHz dual-core Intel Core i5 processor (Turbo Boost up to 3.1GHz) with 3MB L3 cache

Intel HD Graphics 4000 (all 13- and 15-inch configurations)
NVIDIA GeForce GT 650M with 512MB of GDDR5 memory (15-inch 2.3GHz configuration) or NVIDIA GeForce GT 650M with 1GB of GDDR5 memory (15-inch 2.6GHz configuration) and automatic graphics switching
Dual display and video mirroring: Simultaneously supports full native resolution on the built-in display and up to 2560 by 1600 pixels on an external display, both at millions of colors

It'll run, but you'll have to keep the settings to low. As a notebook GPU it is nowhere near as powerful as the GTX 660 in the OP. Also you'll have to keep background processes to a minimum as DayZ is incredibly demanding on the CPU (due to poorly optimised zombies)

I have 3570k and 7850 OC 2GB with 8GB RAM, and can play dayz maxed with smooth fps (I have high res textures). Only had to slightly lower some settings to remove fps drop in fast combat. With 7870 you should easily be able to play at maxed.

I have post processing disabled, dont know how much fps it would drop, but naturally when playing dayz you should turn it off. Because if its turned on you cant see shit if you try to look at long distant.