Intel Core Duo 2 vs Pentium 4

[Paulst30]

Hey peeps,

Just got around to getting to grips with the inner workings of my Pentium 4 when out pops another "top class" processor.

What is the real difference between these two?

Before you answer i know that:

P4 HT has 2 logical cores
Duo has to physical cores

I know that P4 was built on Netburst architechture, however what makes the core due so much quicker as its not any quicker per clock cycle? and has the same L2 Cache.

[vehelpfulguy]

From the web:

Processors are well equipped with 4MB of Level 2 (L2) cache and an effective front-side bus speed of 1,066MHz (actually 266MHz but data is transferred four times per clock cycle).

Such a large, unified cache and speedy channel to access Ram, among the other architectural improvements, more than make up for the clock speed deficiency of these chips when compared with the 3.6GHz that later revisions of the Pentium D were pushed to.

See here

http://www.itweek.co.uk/personal-computer-worl d/hardware/2160312/intel-core-duo-extreme

[fo3nix]

Clock cycle isn't really much to go on. It's not the most important thing by any means, it's just that IBM-compatible PC users have been brainwashed into thinking that over the years.

The P4HT does some clever tricks (the HT), to trick it into behaving as though it can run two threads at once.

Slight sidetrack: know what a thread is? It's just a way of splitting up a process on a computer into little bits -- little threads. These things can run as separate instances. When you're writing a program is helps to make it as parallelisable as possible, which means that you want to make it so that the program could split in two for brief periods, theoretically. You could then fork each into its own thread. For example, the progam A=B+C could calculate B and C as separate threads, then combine them in the end to find A.

Back to main topic: the P4 HT tries its best to pretend to do more than one thread at a time. The Core2Duo (C2D) is actually two cores and so can properly run one thread on one core and another thread on the other.

The processing of the C2D is also better (65nm process, I believe), which is also of significance as it has more transistors/square cm.

Finally, the C2D is 64-bit, but this is of no significance to you unless you have a fully 64-bit OS and want to do something that requires access to more than 4GB RAM.