I'm assuming it's either "One generation against another", or the Proven Workhorse versus miniaturization and improved capabilities.
Big Brother plays against Little Brother.
Centralized Mini-Computer, against Turbo-Charged Work-Station.
That's just my guess. I have enjoyed reading the Deep Blue development notes against Kasparov, but this is not my area of expertise (I'm a financier, not a programmer).
If you want a more precise answer -- ask IBM. I'm not the guy to answer your question intelligently, sad to say.
My calvinist buddy "CCWoody" is a computer engineer, he knows this subject better than do I. At least he can probably comment more intelligently than can I. I'll flag him in.