[QUOTE=Mini-Geek;237629] if you want to experiment, tell Prime95 to put that worker on a specific core and see what happens to the speed and what appears in the task manager) [/QUOTE]

[QUOTE=CRGreathouse;237630]It's switching between cores. If you like you can set processor affinity for the thread and see if there's a performance difference; I doubt it.[/QUOTE]
Thanks for your patience and suggestions, I will definitely try that.

[QUOTE=otutusaus;237634]Mr. Silverman, I started posting less than a week ago and I am still getting familiar....
I regret having to read posts like yours. Please be more respectful and tolerant with other people's ignorance.[/QUOTE]That is Bob. Ignorance is one thing, but if he sees an unwillingness to learn, he gets testy.

[QUOTE=R.D. Silverman;237627]
If you want to be argumentative, go somewhere else.[/QUOTE]

On the contrary: if he's looking for an argument, he's
come to the right place.
Or is this abuse?

David

[QUOTE=Uncwilly;237717]That is Bob. Ignorance is one thing, but if he sees an unwillingness to learn, he gets testy.[/QUOTE]

The issue is not ignorance. He asked a reasonable question.

But after he was given a response from several different posters
he still continued to argue about it.

I understood the fact that it is more efficient to run FT in a single core than to divide the job between cores. All answers were clear about that. I wasn't arguing about that anymore. This is settled. Single core is best. Thank you for your explanations.

What I was stating later is that it looks as if the FT in Prime95 is running shared between cores (according to what I see the Windows Task Manager).

Anyway, I've run FT tests using different settings (Smart assignment in 1 thread/2 cores, Run on any CPU in 1 thread/2 cores, Run on any CPU in 1 thread per core, or as CPU #1 in 1 thread) and all timings are the same.

[QUOTE=R.D. Silverman;237798]The issue is not ignorance. He asked a reasonable question.

But after he was given a response from several different posters
he still continued to argue about it.[/QUOTE]
That does not go against what I said.

[QUOTE=otutusaus;237801]I understood the fact that it is more efficient to run FT in a single core than to divide the job between cores. All answers were clear about that. I wasn't arguing about that anymore. This is settled. Single core is best. Thank you for your explanations.

What I was stating later is that it looks as if the FT in Prime95 is running shared between cores (according to what I see the Windows Task Manager).[/QUOTE]
It may look a bit like it in Task Manager, because Task Manager would be doing some time-averaging. What you are seeing is prime95 being switched between cores (as CRGreathouse said earlier). This means it runs on one core for a time, then is moved to another, ..., at the whim of the OS. From our (human) perspective this can happen very quickly. This is [B]not[/B] the same thing as multithreading, where an application runs on two or more cores at the exact same time.

[SIZE="1"]Disclaimer: Regarding computers, I am an untrained lay-person. (IANAL equivalent.) Doubtless there are exceptions & more precise definitions than my essay.[/SIZE]

[QUOTE=R.D. Silverman;237798]The issue is not ignorance. He asked a reasonable question.

But after he was given a response from several different posters
he still continued to argue about it.[/QUOTE]

God you are such a reasonable man.

David

PS If you need any more ammo, try my latest post
in the music thread.

[QUOTE=otutusaus;237801]I understood the fact that it is more efficient to run FT in a single core than to divide the job between cores. All answers were clear about that. I wasn't arguing about that anymore. This is settled. Single core is best. Thank you for your explanations.

What I was stating later is that it looks as if the FT in Prime95 is running shared between cores (according to what I see the Windows Task Manager).

Anyway, I've run FT tests using different settings (Smart assignment in 1 thread/2 cores, Run on any CPU in 1 thread/2 cores, Run on any CPU in 1 thread per core, or as CPU #1 in 1 thread) and all timings are the same.[/QUOTE]

You may try [URL="http://www.dewassoc.com/support/useful/wintop.htm"]Wintop[/URL] to check timings on different threads.

Luigi

[QUOTE=markr;237841]This means it runs on one core for a time, then is moved to another, ..., at the whim of the OS.[/QUOTE]

This is correct, and is true on most* OS and most* hardware.

The reason is that it makes for more even heat generation/dissipation within the CPU => cooler => more reliable => longer lifetime.

* most = all, in my personal experience, unless affinity has be used to override this.

[QUOTE=Vato;237933]The reason is that it makes for more even heat generation/dissipation within the CPU => cooler => more reliable => longer lifetime.[/QUOTE]Thanks for pointing this out. It's something I'd hardly ever consider.

[QUOTE=Vato;237933]* most = all, in my personal experience, unless affinity has be used to override this.[/QUOTE][I]Does that mean that using affinity to assign particular GIMPS tasks to particular cores could, theoretically, reduce CPU reliability and/or lifetime[/I] (compared to the case where the OS periodically rotated tasks among cores) [I]if some of those tasks were more CPU-intensive than others?[/I]