4 games =! all games.
you should have properly linked anandtech's bech comparison for the two rather then a photobucket image of a cropped portion of it without labeling which CPU is what.
http://www.anandtech.com/bench/Prod....36.37.38.39.40.41.42.43.44.45.46.47.48.49.50
here is the link.
Indeed for fallout 3, left 4 dead, far cry 2, and crysis warhead the phenom II x3 @ 2.8ghz outperforms the athlon II x4 @2.8 ghz.
I would like to see some benchmark for unreal 3 engine which is very good at making use of quad cores. As well as supreme commander.
here are a list of UE3 engine games:
http://en.wikipedia.org/wiki/List_of_Unreal_Engine_games#Unreal_Engine_3
for all the accusation of being canned, 3dsmark does a pretty good job in many respects. here is an example from it:
http://www.firingsquad.com/hardware/amd_propus_athlon_2_x4_630_620_performance/page5.asp
And yes, elsewhere in the article the compare crysis and farcry 2 and left 4 dead just like anandtech did and those three shows the advantage to the P2 X3 over the A2 X4.
I am still looking for comparisons of good quad core utilization like UE3 engine games (ex: mass effect 1&2) or games like supreme commander.
Why does it matter?
Lets look at the engine of each game:
Fallout 3 uses the same engine in oblivion.
http://en.wikipedia.org/wiki/Gamebryo
Far Cry 2 uses:
http://en.wikipedia.org/wiki/Dunia_Engine which is unique to itself... it is the only game with that engine and its performance is unique.
Far Cry 1 used the cryengine 1, shared only by it and Aion: Tower of Eternity
http://en.wikipedia.org/wiki/Cryengine
Crysis warhead is an expansion of crysis, both and a slim picking of in development games use the cryengine 2
http://en.wikipedia.org/wiki/CryEngine_2
interesting that one game Entropia Universe switched from Gamebryo to cryengine 2 via a patch... Raises questions about their similarities and possible collaboration between the companies.
here is the family tree of CryTek engine games
http://en.wikipedia.org/wiki/File:CryEngine_family_tree.png
In all those games are a very specific slice of games known to be extreme under-performers. using related game engines (far cry and crysis especially).
However, you do have an outlier, Left 4 Dead uses the source engine
http://en.wikipedia.org/wiki/Source_(game_engine)
the source engine actually has some decent standing and a wide array of games; I would definitely take the performance in a source game to be a good sign... it is also old enough and non demanding enough that propus gets 95 fps and heka gets 110 fps... recall that your monitor is limited to to 60fps unless you are using nvidia's 3d thing with the glasses (and a capable monitor) in which case you need 120 fps. (source engine debuted in 2004... IIRC the first dual core processor came out later than that; although, naturally it has been improved since)