computers

It's pretty self explanatory, Core 2 DUO has two cores, Core 2 QUAD has four cores.

I GOT A QUESTION. WHAT OPPERATING SYSTEMS/PROGRAMS ACTUALLY MAKE USE OF DUO OR QUAD OR DUAL.

greg

Windows XP on up, and modern Linux kernels should.

On XP, type Ctrl-Shift-Esc and click on the Performance tab. You should see TWO windows (for a dual core chip) under CPU Usage History. Dunno if that works for quad cores.

Michael

Forgot to mention - after hitting Ctrl-Shift-Esc, click View: CPU History, and click "One Graph Per CPU". It might not be selected by default.

M

Win2k also supports multiple processors.

Does it really improve performance, or is it simply a marketing gimmick?

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
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         America: Land of the Free, Because of the Brave

In real life it makes a big difference when you're doing several things at the same time. Say unzipping a large archive while doing something else. When I had a single-core cpu compacting messages in OutlookExpress rendered my PC useless, now I can do that in the background while I do something else.

General feel while using a multi-cpu computer is definitely much better, however I think going beyond 2 probably does not make much of a difference, if any.

Other than that, the only applications that make use of multiple processors directly are some graphics programs, some video editing software and 2-3 advanced games.

And yes, Seti runs much better, almost 4x faster for a quad cpu :)

M

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

There is a real improvement, but it depends largely on...

1) Do you tend to run multiple programs that are both CPU intensive at the same time? 2) If not, do you have any single programs that are multi-processor aware and internally divide their workload between them?

With two cores you don't usually get very close to 2x performance in "real world" applications -- 1.75x is considered very good. With four cores getting

3.5x performance is doing quite well...

There are some multi-threaded (able to use more than one core simultaneously) SPICEs out there (e.g.,

, although AFAIK they've always been in the realm of more exotic/high-end/"developmental" SPICEs.

I'm installing an acquisition system that can make use of two processors. The guy programmed it that way. I understood that in Win2K you had to use a program that was programmed for two processors.

So it seems what I'm, hearing is that in XP, ANY program will be split as necessary between processors ??

greg

No; WinXP is still the same as Win2K in this regard.

A program consists of one or more threads. Unless specifically told not to, Win2K/XP/etc. will schedule *threads* across multiple CPUs. The scheduling algorithm tries to be smart, though, and *usually* the same thread ends up on the same CPU, the idea being that there's a great likelihood of cache hits if a thread executes on the same CPU as it did previously, even if some other process's thread was scheduled inbetween. (Although again here a program can tell the scheduler that is has no "affinity" for a particular CPU if it likes and adjust a few other scheduling parameters.)

In general there's no way of automatically splitting program execution at a finer level than that of threads because it becomes effectively impossible (at least, "on the fly") to figure out the dependencies between different parts of a thread (e.g., what parts can be executed in parallel, which depend on the order of execution, the availability of prior results, etc.).

---Joel

guy

that

necessary

That is impossible in general (as far as I know). It might be possible to allocate each thread, of a multithreaded program, to a separate CPU.

--

John Devereux

Or in fact, do you run one program and want to see its output at the same time? Display rendering is a heavy task, and having 2 CPUs enable the program to get on with things unrestricted by having to drive the display as well.

More than 2 CPUs is overkill for a desktop, unless you use particular programs that take advantage of them.

It depends on the program (or mix of programs). It's really nice when you have a single threaded calculation intensive program running, you can still work on a user application program without having to wait between keystrokes.

Any well threaded application should be able to take advantage. Somewhat to my surprise I found Gravity (newsreader) makes good use of multiple processors (at least as of NT4 and I doubt it's changed). Seeing that it is able to pin two processors at times I'd be curious as to whether it could take advantage of more effectively.

Robert

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Posted via a free Usenet account from http://www.teranews.com

Fascinating; thanks.

As others have stated, it makes a difference even if programs are mono-threaded and you're running them concurrently. Unfortunately, PSpice doesn't take advantage of muliple processors. LTspice, I believe, sort of does since the graphing portion is on a different thread than the solving portion. Xilinx's tools for compiling and routing FPGA stuff takes advange of muliprocessor environment with a very noticable improvement in completion time. Slowly, engineering apps are starting to use multiple threads. Multimedia programs like Photoshop and Vegas Video are multi-threaded.

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Mark

Great! Now I have both cores recognized on my Win2k machine.

The

link was the more helpful one...

Michael

Ooops, error, Xilinx's tools don't support multiple processors yet. We got a major improvement due to memory speed (The old Athlon's had horrid memory transfer rates).

Xilinx' tools may not support multiple processors but a dual processor system doesn't turn to glue when doing P&R. I used to have two systems (one only for P&R).

--
Keith