On 12/28/2012 02:13 AM, Damaeus wrote:
In news:alt.comp.hardware.amd.x86-64, Wes Newell
posted on Fri, 28 Dec 2012 03:43:47 +0000 (UTC)
the following:

On Thu, 27 Dec 2012 18:42:37 -0600, Damaeus wrote:

Is a Six-Core at 3.5 GHz going to be faster, overall, than a Quad-Core
running 3.8 GHz?

Depends on the threads running. If all 6 cores can be used to the max
then the effective speed is 3.5x6, or 21Ghz, while only 4 is 4x3.8, or
15.2Ghz. So the 6 core is potentially 30% faster.

Okay, thanks. That makes sense. Learning all the time.

I was using a dual-core before I built this temporary system that only has
one core. It's extremely painful to use.

I'm going with the 6-core. The 8-core is a little out of my reach with
the other stuff I need.

For an ordinary desktop user, there is a great advantage in
shifting to a dual-core cpu from single-core. Beyond dual-core,
the benefit of more cores depends on how many processes are
running and how long they need to run at a time for high
throughput If you have a lot of processes going and several that
need a core for long periods of time at a stretch (relatively, of
course, in cpu time -- not long by user time), more cores will do
better. But generally, gains beyond dual-core are usually not
apparent and the added overhead can in fact slow things down.

I have a couple of machines, one dual-core and one eight-core,
both running the same OS, very similar configuration, and similar
workload. The dual-core is actually much snappier in response
time most of the time, but when it gets overloaded (copying
massive files while browsing the 'Net or other multiple heavy
loads) it will bog down. The eight-core is slightly slower but
smoother in response time and never ever gets bogged down enough
to affect more than the one process that is hogging a core.

There is also the consideration that four and six core cpus often
were manufactured as eight-core, and cores that failed QA tests
were disabled. If some of the cores failed, it can suggest a
problem with the entire piece of silicon. That usually shows up
as an infant death, though, so at worst you might need to go
through the return-merchadise-authorization routine to get a
replacement.

Cheers!

jim b.


--
UNIX is not user unfriendly; it merely
expects users to be computer-friendly.