On Sat, 18 Nov 2006 07:45:20 -0500, Neil Jones
wrote:

Hello,

I am seeing a lot of marketing of Dual Core systems. As you have
guessed, I am not a hardware geek. What is the big advantage of dual
core systems? I know it is like having 2 processors. Will each core
perform at the high GigaHertz speeds that the marketers used in the past?

The umm, big advantage of dual core is that it gives CPU mfrs something to
do with the additional chip real-estate as they go to smaller and smaller
IC geometries:-)... a bit cynical but there's nowhere else to go at
present. The clock speed ramp is tapped out until some potential
fundamental material science breakthrough - it'll likely climb a bit but
more slowly than historically.

There are differences between Intel & AMD's approach but it *is* like have
two processors... but since they're on the same chip, they share the same
memory bus. In the worst case, if you had two tasks with very high memory
bandwidth requirements, they'd probably run in shorter time if run
consecutively than if run concurrently. In the best case you can run two
fairly compute/memory intensive tasks efficiently or have one moderately
intensive task and also have the system still respond to user inputs for
another less intensive task.

Current dual core chips are backed off on clock speed slightly from what
can be done with a single core but not by much... and not enough where
you'd regret getting the dual vs. the "faster" single-core.

I have a single core system at home and a dual-core of the same clock speed
and memory bandwidth at work and the difference in response is noticeable -
with dual cores you see much less of the hour glass when trying to do two
things at once.

I plan to buy a new PC sometime early next year. Does the current
software technology take advantage of the dual core hardware? Is there
significant performance speed on the system?

I think the best one can say at the moment for the software is that "it's
getting there". Ideally we'd have tasks with multiple threads of execution
which could run entirely simultaneously for a tangible benefit but that'd
be rare for most common tasks and then if we had err, quad-cores we could
run two dual-threaded tasks simultaneously without suspending one task
while the other runs. I have my doubts that anyone's going to realize any
real benefits of quad-core CPUs for a while... at least on the desktop.

Game makers are curently working on multi-threading their CPU work-load -
they have to for the most recent game consoles anyway so there's some
fallout there for the PC desktop. I'm not a gamer so don't follow it
closely but maybe someone else can comment.

The bottom line is that yes, it's worth getting the dual-core system even
now, especially given the price-point vs. single core. If you assume some
reasonable gain in software redesign and coding you come out ahead vs.
single core. My crystal ball says that a CPU bought now could have a
relatively long life-cycle before you'd even be tempted to look for
something better... but I've never been much good at reading crystal balls.

--
Rgds, George Macdonald