GHZ vs Cores?

Can somebody please tell me why a chip that is a P4-3.2 ghz is a lesser
performer than a P dual core 2.6 ghz? Intel is really messing up my
upgrade thoughts! Thanks.

Quite a few reason for dual core performs well than a single core at higher
clocks,

- Higher or more Cache, usually shared between 2 cores so that your
application threads execute on both cores at the same time and they get
info(data). from their shared cache instead of depending on large and slower
cache in single core.
- Applications itself can be made to use dual core technology extensively.
- More efficient Cpu design,Cache distribution, Access time for
cache,memory controllers.

For more technical overview Search www.google.com for "Dual core vs single
core cpu's"

Cheers




"ajb" wrote in message
...
Can somebody please tell me why a chip that is a P4-3.2 ghz is a lesser
performer than a P dual core 2.6 ghz? Intel is really messing up my
upgrade thoughts! Thanks.

On Thu, 14 Sep 2006 22:22:33 -0400, ajb wrote:

Can somebody please tell me why a chip that is a P4-3.2 ghz is a lesser
performer than a P dual core 2.6 ghz? Intel is really messing up my
upgrade thoughts! Thanks.

The P4 was designed to do nothing fast. Specifically the problem was that
it had a very long pipeline, something like 30 stages. The long pipeline
allowed it to run at high clock rate because less had to be done in each
stage. The problem with a long pipeline is that code is full of branches,
as I recall from my days of designing CPUs, branches occur every 4 or 5
instructions. You can predict the direction of many but not all branches.
When you guess wrong about the direction of a branch you have to flush the
pipeline, the longer the pipeline the more instructions you have to throw
away. That's why the P4 was so inefficient, it spent a lot of time
executing instructions that it ultimately had to throw away.

The PII and PIII had short pipelines and thus were more efficient, it was
the P4 that was different. The long pipeline and resulting high clock rate
worked for Intel for several years. Most people assumed that the a highest
clock rate was the same thing as the highest speed so as long as Intel
could keep pushing the clock rate up they were in a good marketing
position. However they ran into a limit due to heat. The faster the clock
the higher the power consumption. The P4 reached a point where it couldn't
be cooled any more so Intel couldn't keep pushing up the clock speeds. In
the mean time AMD came out with the Athlon 64 which had a short pipeline
and a on board memory controller. The A64 was much more efficient than the
P4 so it was able to run programs faster at a fraction of the heat.
Eventually AMD took a huge amount of market share from Intel.

Intel has finally responded. The new Core2 has a short pipeline and a huge
cache. The Core2 is faster than the A64 and consumes about the same power
when fully loaded.

ajb wrote:
Can somebody please tell me why a chip that is a P4-3.2 ghz is a lesser
performer than a P dual core 2.6 ghz? Intel is really messing up my
upgrade thoughts! Thanks.

Forget all the technical talk about cache size, application threads,
and long pipelines...Everything is simply a lot faster, smoother.
Period.

I use both Pentium-M (single) and a Core Duo laptops...there's no
comparison. There is no compelling reason in my mind to ever get a
single-core system.

Case in point: Last night I was doing an sfc /scannow on my single-core
system...I couldn't do anything while this was in process (about 10
minutes). Everything slowed down to a crawl. The Pentium-m was
basically brought to its knees.

This doesn't happen with my dual core. I can go merrily on my way and
do other tasks will the computer is doing something else. I can't tell
how much better this makes the computing experience.

The poorly designed P4 3.2 GHz processor used VERY long pipelines internally
that slowed down the effective real processing speed of the CPU. The new
CORE 2 Duo's use well designed short pipelines, run much cooler, and are FAR
more efficent in running high speed computations than the older P4's.
Higher GHz speed does NOT always mean the CPU runs faster in the real world.

--
DaveW

----------------
"ajb" wrote in message
...
Can somebody please tell me why a chip that is a P4-3.2 ghz is a lesser
performer than a P dual core 2.6 ghz? Intel is really messing up my
upgrade thoughts! Thanks.

On 15 Sep 2006 15:10:11 -0700, wrote:

ajb wrote:
Can somebody please tell me why a chip that is a P4-3.2 ghz is a lesser
performer than a P dual core 2.6 ghz? Intel is really messing up my
upgrade thoughts! Thanks.

Forget all the technical talk about cache size, application threads,
and long pipelines...Everything is simply a lot faster, smoother.
Period.

I use both Pentium-M (single) and a Core Duo laptops...there's no
comparison. There is no compelling reason in my mind to ever get a
single-core system.

Case in point: Last night I was doing an sfc /scannow on my single-core
system...I couldn't do anything while this was in process (about 10
minutes). Everything slowed down to a crawl. The Pentium-m was
basically brought to its knees.

This doesn't happen with my dual core. I can go merrily on my way and
do other tasks will the computer is doing something else. I can't tell
how much better this makes the computing experience.

1.) A few specs on the 2 machines?
2.) You have run comparisons with a single-threaded
application and/or garden variety apps (i.e.
browser, Email, editor, etc)??

Al

"The monkey and the baboon was playing 7-up.
The monkey won the money but he scared to pick it up.
The monkey stumbled, mama.
The baboon fell.
The monkey grab the money and he run like hell!"
- from "Motherfuyer", Roosevelt Sykes, around 1929