LSMFT said:
If I build a new pc with a new motherboard and processor, how many cores
are necessary and or used. Is x2 still adequate? or should I go for 3,
4, 7 or what?
If you grossly mismatch the processor to the set of tasks, what
you're doing is wasting electricity on the cores that aren't
being used.
If the machine was for email, Microsoft Office, web surfing,
you could easily get away with a high clock rate dual core.
If you always have a DVD Shrink running in the background,
do video editing, process large Photoshop posters, perhaps
a quad would make more sense.
For gaming, core loading tends to be asymmetric. Usually one
thread of execution is running one core at 100%, while
the other cores are loaded to 30%. You might see a 100-30-30-30
loading pattern on a quad. So the quad doesn't run games
four times as fast. Balancing the threads of execution is
difficult.
Changing a program from a single thread of execution, to
multiple threads, is difficult enough. Changing it to run
on an arbitrary number of cores, efficiently, is even more
difficult.
To give an example, Excel has added to it, the ability to
compute on more than one core. But the list of exception
cases, things that can't be run in parallel, is as long as
your arm.
Photoshop filters are divided into two sets. One set runs
on a single core. The other set runs on multiple cores.
It is unclear what the upper limit on cores is. Not all
Photoshop operations, as a result, get all the benefit
from a large number of cores. It depends on what operations
you do a lot, as to how Photoshop would scale.
When I was using Windows Movie Maker, only the final rendering
uses multiple cores. The editing/interactive stage, seems
to use one core.
Is there a place for a 6 core processor ? At some point,
this practice has got to have diminishing returns. You can
run Cinebench on a fairly large group of cores (it is known
as a perfect scaling benchmark). But once you've got past
your first hour of running benchmarks, what real world thing
really runs well on an infinitely large set of cores ? Is it
worth spending more, for that opportunity, of running a couple
of programs only, with more computing power ? If you
do video editing all day, probably yes. If you want
"future proofing" (on the chance some game will do a better
job of thread balancing), a quad should be plenty.
You can spend hours analyzing these things. For example, here,
some games are GPU limited, and some other results just don't make a
lot of sense (in terms of the benefits of overclocking). If you played
one game a lot, and that game happened to be measured in this article,
you might make your processor choice based on the results.
http://www.xbitlabs.com/articles/video/display/radeon-hd5870-cpu-scaling.html
My electricity rates will be going up here soon (to help pay
for things like wind power and solar). And I'm pretty happy
to be using a dual core, as a result. My current 65W dual
core, uses 43W flat out, and 6W idle. If it was a quad,
I'd likely see about 12W idle, which still isn't that bad.
The rest of the computer wastes more power than that.
You can see some video card power measurements here. One of the cards
is only drawing 15.8 watts at idle, which is an improvement over
previous generations. That allows you to build a gaming box, without
feeling too guilty. In previous generations, a "fire breathing"
video card, wasted lots of power all the time.
http://www.xbitlabs.com/images/video/gigabyte-gf-gtx400/gtx400_power.png
http://www.xbitlabs.com/articles/video/display/gigabyte-gf-gtx400_6.html#sect0
Paul
