I don't get why several people here are calling this guy a troll. He seems earnestly looking for a solution, is asking questions, and taking advice. WTH guys...
Anyway while it is true you can run MindCraft natively in OS X some of the built maps are pretty high poly count and include physics, bots, logic and etc. Simple worlds would run fine on a $400 mac but I dunno about the complex ones... I kinda doubt it.
Also, who only plays one game. Usually gamers like variety. I have over 2,000 on C=64, about 900 on Amiga, 35 or 40 on Mac (although about 10 or 15 of those stopped working under 10.7

), and about 120 for Windoze. And I'm not even a gamer.

Battlefield III runs well on my son's PS4

Very populated MP servers too.
I haven't looked into it myself but I guess if you're buying new then maybe the best you'll get is the APU type system being mentioned but aren't used gaming boxes selling for $400 to $500 with damn decent secs? I would think so anyway.
This:
- AMD PHENOM II X4 965 QUAD CORE PROCESSOR 3.4 GHz
- 16 GIGS OF 1333 RAM
- AMD RADEON 5750 1 GIG VIDEO CARD
- 256 GIG SAMSUNG SOLID STATE DRIVE
- 1 TERRABYTE 7200RPM STORAGE DRIVE
- WINDOWS 7 64 BIT HOME PREMIUM
- USB 2.0, USB 3.0 AND FIREWIRE
- DVD RW DRIVE
- LOGITECH MOUSE & KEYBOARD
- (MONITOR NOT INCLUDED)
recently sold for $500 after shipping.
Here's one that sold for $460
- Intel Core i7 2600 3.4 GHz processor; for top-ending gaming performance
- 8GB of DDR3 memory; ensures uninterrupted gameplay
- 1TB 7200rpm HDD; provides more space to secure all your games and other multimedia files
- 1GB NVIDIA GeForce GTX 550 Ti GPU; delivers life-like visual performance
And I see quite a few others with similar specs which have recently sold for similar prices:
http://www.ebay.com/csc/i.html?LH_I...kw=used+game+PC&LH_Complete=1&LH_Sold=1&rt=nc
I guess there are such active deals happening currently as well:
http://www.ebay.com/sch/i.html?LH_I...mPrRngCbx=1&_udhi=500&_nkw=used+game+PC&rt=nc
http://www.ebay.com/sch/i.html?_odk...311.R3.TR3.TRC1&_nkw=used+pc+desktop&_sacat=0
.