The new pentium 4 core codenamed Northwood which came out in january 2002, is pretty much identical (from the architectural point of view) to its predecessor : the Pentium 4 Willamette.
There are only three differences :
- The use of 0.13µ manufacturing technology for the Pentium core (against the previous 0.18µ for the Willamette)
- The L2 cache increase (512KB instead of 256KB)
- The size : 145mm2 against 214. This should make the Northwood cheaper because Intel can fit more dice on a wafer
As the chip frequency grew higher according to Moore's Law, the urge to find a new cooling system grew proportionnaly. The fact that the Willamette core isn't very hot can be confusing at first because the heat dissipation isn't distributed evenly on the surface of the chip. In any case, Intel had to change the technology in order to reduce the heat. Hence the new 0.13µ, which allows a lower voltage for the core (1.475V instead of 1.75V). For a 2GHz clocked P4, the Power decreased from 69W to 41W, greatly lowering heat dissipation.
Besides the L2 cache increase, there weren't any architectural improvement, so comparing a Northwood with a Willamette on the same clock speed (2GHz) using pure CPU processing algorithms (no memory use) gives out the same results.
The new Northwood comes in two flavours : 2.0AGHz and 2.2GHz. The Front Side Bus is still 100MHz (Quad Pumped 400MHz) on a 478 socket exclusively
In april Intel will be introducing two new chips : 2.26GHz and 2.4GHz featuring the new 133MHz FSB (Quad Pumped 533MHz)
Now the question is : When am I going to change that old PII 300 I'm using since 98?