Intel CPUs Numbers and Pricing -- Confusing

[Harper]

Just what is Intel trying to prove with their current CPU pricing?

Like we got the INTEL: 530J-PENTIUM 4 3.0GHZ 800FSB LGA775
and the INTEL: 531-PENTIUM 4 3.0GHZ 800FSB LGA775

Both come with 800FSB,
Both come with 1Mb Cache
Both come with the same Heatsink (non of this BTX business)
Both currently avalable on the market.
However the 530J comes with about a $100 more price tag than the 531.

And again, things are confusing with Dual Core
945 - PENTIUM D 3.4GHZ 800FSB
950 - PENTIUM D 3.4GHZ 800FSB
Again $100 difference

Now to the joe average computer user's eyes, what the advantage of having simulare CPUs with totally different price tags?

Like sure, there might be some difference like Cache, FSB, Core Revision or some other new technology wank word that suppose to make it better. But how does this all helps out with Joe Average that just wants a computer.

 

[STATus h2O]

The difference in L2 cache increases performance by as much as 10%. Users will notice slightly faster speeds in the acces of programs, but nothing that will dramatically increase performance. Joe Average can be told that the difference in Cache will increase the speed seen with the naked eye just slightly, and increase performance by a small margin.