Actually, Titan, there is a $45 difference between the 2.4B and 2.4C at Newegg. The difference nearly doubles for the 3.0C and 3.06B.
Anyway, F4, if you're concerned with application performance the difference is going to be barely perceptible at default speeds. If you look at the tests for the new C chips you typically see less than a 10% difference in framerates for game tests. For CPU intensive titles like Commanche 4 the difference is less than five percent for similar speed chips. You won't see that on your monitor.
That's at default speed. If you overclock it might be even harder to justify spending the extra money for a 800MHz chip. So far the 800MHz chips are reaching a couple hundred MHz higher than the last generation of 533 B's in benchmark racing. Every MHz counts, of course, and if you have to have the fastest system a P4-C is the way to go. But a couple hundred MHz clearly isn't the kind of breakthrough a lot of people expected from a 50% bump in the FSB speed (from 133 to 200) and a 12 multiplier (for the 2.4C).
What's happening is the increase in FSB has exposed another limit in the 0.13u P4. Until now you'd hit the wall on vcore before the processor temps became a critical issue. But guys overclocking 800MHz chips are reporting just the opposite. Temperatures hit the wall before you have to raise the voltage. And even with phase-change cooling the raising the vcore above 1.65v does not improve speeds as it would in the B's.
Long story short, we have reached the limit of what the Northwood chip can do. Regardless of cooling medium or default FSB speed, that is roughly in the neighborhood of 3.4-3.6GHz for sustained use with a good chip.
For these reasons I think the smart setup for this last cycle of the P4 is going to be a good B chip like the 2.4 on a good 865PE board.
BHD
