Crysis 2 will run fine with a dual core, Recommended settings are a dual core.
Bulletstorm will run perfectly on a dual core.
Deus ex will again run perfectly on a dual core.
GTA IV runs perfectly on a dual core.
Also these aren't engines.
They run on an engine, which if its described by the name generally means they just don't know the specific engine name but the person listening or reading usually gets the gist of it. Many engines now utilize multiple cores, two, three or four, saying that they don't usually means you don't know the engine. Play some game like TF2 with a dual core and then with a quad, there's a difference maybe not as great as saying BF3, MW3, CS:GO, or other games out there now, but you'd be surprised that quad cores help more than you think. Also Crysis 2 with a dual core... okay then. Tell me how that works out....
By the way, quad cores are the best way to go for gaming. Saying a dual core will run games that someone may play fine is a joke maybe 5 years ago that was the case, but developers are starting to fully utilize multiple cores and it shows. Friends and family ask me for advice on building computers for gaming and I always tell them quad core, AMD or Intel.
This is 2012, a quad core is cheap now. Why waste the power and time on something less? A Phenom II X4 goes for no more than $119 (or so), a dual core will go for half of that. A Core i5 (Quad Core) will go for $189 to $249, while a Core i3 is half or slightly over half of that. So why not just double it now and just get a quad core, that way you save time and energy of having to replace it later.
Anyways Huckleberry's CPU/RAM/Mobo/GPU selection will work fine, but could opt out of that SSD, as for the same price it will have probably doubled in size or moved to a PCIe (I plan on buying one when I actually am not in debt from college loans D:! ) slot for even faster data transfer and reading by this time next year.
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Engine Specifications:
Source Engine (Valve Software) : Multiprocessor support (2007, The Orange Box),
http://en.wikipedia.org/wiki/Source_Engine
CryEngine ( CryTek ) : Multi-core support,
http://en.wikipedia.org/wiki/CryEngine_2
Civilization 5 Game Engine [Unknown Name] ( Firaxis ) : Minimum requirements: Intel Core 2 Duo 1.8 GHz or AMD Athlon 64 X2 2.0 GHz Processor, Recommended: 1.8 GHz Quad Core Processor,
http://en.wikipedia.org/wiki/Civilization_V
IW Engine ( Infinity Ward ) : Minimum Requirements: Intel Core 2 Duo E6600 or AMD Phenom X3 8750 processor or better,
http://en.wikipedia.org/wiki/Call_of_duty_modern_warfare_3
Deus Ex: Human Revolution [Modified Crystal Engine] (Eidos Montreal) : Minimum Requirements: 2 GHz dual core CPU, Recommended: AMD Phenom II X4 or Intel Core 2 Quad or better CPU,
http://en.wikipedia.org/wiki/Deus_Ex:_Human_Revolution
Unreal Engine 3 ( Epic Games ) "...multi-processor performance",
http://www.unrealengine.com/en/features/
I could go on, but you can see a pattern arise. They either are capable of using multiple cores or require at least a dual core, but for the best or most fluid experience a quad core is generally recommended. Yes I cited Wikipedia, but I could just go on Steam and access the requirements for the games or the games that use those specific engines. Also not many Engines are available for specifications probably due to being proprietary software.