Dual Core vs Single Core in Gaming

Ok folks. I HAD a P4 2.8
I then got a Pentium D 820.... found out the benchmarks were about the same as the P4 2.8
THEN, because Im a gamer, I decided to sell my new rig and get a AMD X2 3800 at 2.0 MHz.
Now my question is, since the X2 is @ 2.0 MHz, yet the P4 was @ 2.8 MHz, and some games arent written to take advantage of a dual core..... is my performance the same, better or worse in games with what I have now.
Im a tad confused. Does MHz really mean anything anymore?

Thanks in advance.

Thanks for the quick reply.
What is the rating scheme thats being requested?
Being italian, I suggest a pizza sliding scale. One topping.... two toppings..... etc.

Pentium 4 = Little Caesar's $5 Pizza that's been in a dumpster since Monday.

AMD Toledo = Little Caesar's $5 Pizza that's been in a dumpster since Tuesday.

AMD Brisbane = Vending Machine Mini-Pizza

Quad FX = Two Vending Machine Mini-Pizzas

Core 2 Duo = Chicago Style Deep Dish with Pepperoni & Mushroom

Core 2 Quad = Wood Oven Fired Margarita from Brandi Pizzeria in Naples (the place that invented that pizza in 1889)

Penryn (and possibly Barcelona) = Pizza Orgasm

In Naples, if you ask for a "Margarita", you get a cocktail containing tequila, triple sec, lemon and salt.

Lol.
Well, in Italy, "peperoni" (without the "pp" ) means "peppers" (the non spicy ones).
So you won't get any salami on it, just a fully vegetarian stuff

PS: as an Italian, i didn't even know what Capacola is. I had to look it up in wiki, we call it "Capicollo"

No.


Well.. If MHz/GHz doesnt mean anything, then why do people still OC the crap out of their CPUs? I mean, if you see a performance gain when your OC an E6600 to say 2.9GHz, then surely that shows that clock speed does mean something.. However, the reason why a 2GHz AMD 64 chip is stronger than say a P4 3GHz, is because it can do more operations per clock cycle..