Personally I think they are badly written
for example world in conflict...
Os Windows XP or vista
Cpu 2ghz or faster (2.2ghz for vista)
Now my Cpu is only 2.1ghz but its a core2duo so It should run it fine (Its installing now

), I suspect they are still using the old P4 ghz ratings.
But that would confuse most people who have say a 1.86ghz core2 processor becuase they'd think its not fast enough when in reality it probably is since the core2duos and althon64 proccessors are far more effecient than their P4 counterparts.