Spec Comparison Question - Pure Processing Power

[Alty]

How much of a difference would you likely expect to see going from these two workstations:

Intel P4 3Ghz
2Gb DDR 3200 (@566Mhz?)
566Mhz FSB

to

Intel Core Duo 2 2.4Ghz (1066Mhz)
4Gb DDR2 8000 (@ 1066 Mhz)
1066Mhz FSB

Basically I am curious as to how much quicker a system would be going from a 566Mhz bus to 1066Mhz bus, especially with the same 1066Mhz speed DDR2 n CPU. Any thoughts?

 

[Alty]

I will be using CPU intensive programs, now I know this sounds noobish but with the ability to multi-task would I be able to thus run 2 CPU intensive programs concurrently or would I be better off just leaving one major CPU intensive program running at a time?