I don't know how the DX2 works, so I'll leave that answer to someone more qualified. But when Apple released the Quadras, there was no talk of an internal frequency. A Quadra 700 was 25MHz, an 800 was 33MHz, and so on. Motorola also quoted the chips as 25MHz, 33MHz, etc...
But then the DX2 was released, and the Quadras benchmarked pretty well against the DX2 chips, and suddenly people were doing the 33/66 thing. I'm not sure if the marketing people at Apple ever jumped on the bandwagon. I am told that whatever Motorola does with the internal frequency is *not* the same as what Intel did with the DX2.
As far as how they stack up - I used to write scientific code in C on both platforms, and they're pretty much even in my experience. In other words my Quadra 700 (25MHz '040) used to about the same as a 50MHz DX2. Now that's just pure processor speed. My understanding is that the Quadras suffered from some bottlenecks in other areas that might not have made them as fast for general computing. And I do know that web browsing will be far inferior to a 486 based machine - for some reason web browsing has always been slower on a Mac than a PC for the same class of processor. You'll find that this isn't just true for the 680x0, but for the PowerPCs too.
But then the DX2 was released, and the Quadras benchmarked pretty well against the DX2 chips, and suddenly people were doing the 33/66 thing. I'm not sure if the marketing people at Apple ever jumped on the bandwagon. I am told that whatever Motorola does with the internal frequency is *not* the same as what Intel did with the DX2.
As far as how they stack up - I used to write scientific code in C on both platforms, and they're pretty much even in my experience. In other words my Quadra 700 (25MHz '040) used to about the same as a 50MHz DX2. Now that's just pure processor speed. My understanding is that the Quadras suffered from some bottlenecks in other areas that might not have made them as fast for general computing. And I do know that web browsing will be far inferior to a 486 based machine - for some reason web browsing has always been slower on a Mac than a PC for the same class of processor. You'll find that this isn't just true for the 680x0, but for the PowerPCs too.