pentium, core 2 duo, duo core?

If a game says Pentium 4 then it is referring to a single core Pentium 4 with no hyper-threading and not the newer Pentium 4 duel cores or the units with hyper-threading. 3.0Ghz in single core P4 is about 1.8-2.0Ghz for a Core 2 Duo or 2.2-2.4Ghz for a Pentium Duel-core.

If you are using pentium4 processor, you need 3GHz. If you are using core2 duo, you need 1.5GHz processor.

3 Ghz is 3 GHz or 3 billion cycles per second. so yes it is the same for all three the dig\difference is the number of processors that are being clocked at that speed the P4 is a single core while the core 2 duo and duo core are dual core Processors, i.e. they have 2 cores. Each being clocked at the same speed so say 3.0 GHz.

As for being able to run a game, if You have a dual core processor contact the game company first to see if it will run with your processor, unfortunately many games only list the speeds for single core computers not dual cores.

Having worked on manufacturing dual core processors, the gain in speed of two prossors at the same speed is around 2/3 faster as a single core at the same speed. with that said you would need a dual core at around 2.4 GHz to 2.6 GHz to run the game effectively.

P4 has only 1 core and it needs a lot of GHz to run a program.

with Core 2 Duo you just need 1.6 GHz to play th same game