Ok lets get this clear for the Computer World crowd. The current crop of Intel Pentiums have evolved like a milking barn on a diary farm. Imagine that when you started out you had cows living on 8 acres of land, now you can only graze so many cows on 8 acres.
When you milk them, you send them through the barn one cow at a time. And they get milked. Later you acquire 16 acres, and then 32 acres and just recently you managed to get 64 acres, and the necessary cows to fully utilize the land to it’s full grazing potent.
Now during this time, you have made some extensions to the barn, you could only milk one cow at a time (8 bit cow), now you you can milk them 8 at a time (8 x 8 bit cows) however you can only put the milking machine on the cows, one cow at a time. You are working alone, after all, you are the core of the farm.
Now you can speed up this processing somewhat by taking on a coworker, another core milker if you will, and you can get the work done more quickly. You could get more acreage, like 128 acres, and maybe increase the number of cows being milked to 16 (8 x 16 bit cows) but then you might need another core or coworker to help out.
Now mind you, we are getting a lot of help with the milking, but what do we do with the milk. We are spending all the time milking and we either need to drive the milk into town, or process the milk and bottle it, make butter, and cheese. What ever, so we need another building to process, except that it cuts into the acreage we need to graze the cows, we need to build up. instead of a two dimensional barn, where the cows are walking in and getting milked, we need to build another floor above the milking floor to process the milk, and another floor to do butter, another to do cheese. We need to expand in three dimensional space. We need to move from milking, or not milking the cows to doing other things, all at the same time.
Not just one thing or nothing (milking or not milking), but maybe doing all the things in between them. And all at the same time. Instead of having the milking crew stop milking, and drive trucks, make butter and cheese. We have more core workers doing other tasks than milking.
The current Pentiums are at that place, needing to have the floors added to milking barn. And guess what, you have to build a better foundation, and ARCHITECTURE to accommodate the new floors to the milking… err Intel processor.