Here I go... One Last Time... Experience has shown me that crossing the path of a List Monitor usually ends up bad for the user, but Hey... Mom never said I was a bright kid.
**Unless an application is specifically written to utilize both processors it will make no difference if you have a 2nd processor. It will sit there idle doing absolutely nothing. --> An application does not need to be written as a multi-threaded application to fork many copies of itself in memory and run many instances of it self. An http web server is a perfect example of this "phenomenon". A graphics program that can run two simultaneous filters may in fact fork two processes in memory that can run simultaneously on two processors. If a large application or service has many "functions" it is very possible that it can start many tasks as back ground processes that will utilize the second CPU Examples of such application services that fork instances of themselves in memory and run as separate threaded tasks on the CPU. - ftpd - telnetd - httpd - NFS - oracle Any command will produce a process, that process will make its way to the CPU. You may be running two applications, my wife the graphic artist of the house usually has 5 apps up at one time, she is constantly reformatting and converting graphic items. - Photo Shop is running a filter - Quark is importing a pic and adding it to a layout - Graphic converter is changing graphic types from one type to the other - iTunes is running in the background - Safari is in there somewhere, along with MSN Messenger It is really a feat to watch that woman go... All the applications are running at the same time, or appear to be running at the same time. Non of the applications have to be multi-threaded to take advantage of the second processor. The Operating system will divide the tasks into two CPU run queues and processes everything for you. It is completely irrelevant if the application is multi-threaded or not. > Two CPU's will allow you to do two things at once. ** No they won't. --> I must have missed the whole story of a multi-tasking multi-user operating system. Mac OS X is BSD Unix under the covers. Perform a "ps -aux" command from the terminal window and you will see multiple processes waiting in the RUN QUEUE. A Dual CPU system has two CPU's as a resource so "two" tasks can run at the exact same time. Review the output of the vmstat command and ps commands over a duration of 1 hour and prove that your system does not have at one point, two or more processes that are waiting in the run queue. A great application is "TOP", It is a freeware application that will show CPU utilization per CPU. You will see both CPUs working on a system under moderated work load. >Does it really matter if applications and the OS are not >multi-threaded? ** Yes it does. As an Apple Certified Technician I attended a recent series of classes on processor specifications and speeds in Cupertino. They new Mac OS X will indeed utilize a dual processor architecture, but very few applications will. Photoshop is one that will. --> A process does not have to be multi-threaded to run on CPU-0 and have a second unrelated process run on CPU-1. This is a function of the operating system, not the application. A process is a "thread" and a "thread" is just a bunch of machine code that really could not care less what CPU executed it. It is a function of the operating system to send the thread to a run queue and the CPU processes the run queue. --> A multi threaded Application is a process that can be broken down into smaller threads that can be executed simultaneously. A multi threaded application is a process that will run simultaneously on two or more CPUs. --> As a student of Computers of a variety of UNIX'S it is completely irrelevant if a task is written as a multi-threaded process or not to take advantage of a multi CPU system. Two independent processes can run simultaneously on a dual CPU. Modern computer operating systems must be MULTI-TASKING capable, this is today's standard. Why focus so much energy on a Multi-User, Multi-Tasking operating system if you are only going to perform a single operation. We had that 20 years ago. It was called DOS. ** If you had them running side by side the 733 would kill the Dual 500 in almost every task. --> Never for a moment did I doubt that the 733 is a "faster" machine. I said the 500 dual can perform two operations at once. A dual system will be more responsive, and more stable. This is a matter of user requirement, not speed. A poor piece of code is going to hang the 733 system, just hang it faster. There is a very good chance that the dual 500 will steam roll its way through a piece of shotty code... --> Do you want to run the latest 3D game on a slower DUAL CPU (assuming the game is not a multi-threaded application)? NO! --> Would you install a single (but faster) CPU over a dual CPU system to be a file server or application server? NO! A Dual CPU system has advantages that are leaps and bounds above a single CPU system. Apple has dumped the single CPU G5 tower from its latest offerings. Apple is pushing Fibre Channel, RAID IDE Disk Subsystems, X-PCI. These are up and coming technologies in industry, something that is out of the hands of the typical web surfer. These advancements need some serious CPU horse power to push them, so much horse power that a single CPU might not have the stones to do it? I will always advocate the use of a DUAL CPU over a single CPU system. Bus Speed, cache, double-data-rate, and other buzz words aside, Two Brains are better then one. A single CPU system will appear laggy and unresponsive under moderate work load. Mouse movement and keyboard commands become a chore. Run the same work load on a slower DUAL CPU system and you will experience a night and day difference. What is more important to the user, true system speed? or the perceived system speed? Never on any dual CPU or Quad CPU system have I had to wait for the command prompt to return, can you say the same about a high end CPU system running under a moderate to heavy work load? Two personal systems (OK NOW IM INTO THE COMPLETELY OFF TOPIC PeeCee GARBAGE SO PLEASE DROP OFF AT ANY MOMENT) - single processor, 1 Gigahertz windows 2000 machine - ide disk - dual processor 300 Megahertz windows 2000 machine - SCSI raid disk YES WINDOWS, PEECEE, INTEL, ALL OFF TOPIC BUT PLEASE BARE WITH ME OR STOP READING - single processor system runs the games well but she laggs up something fierce from time to time. Run a game server, RIP some MP3's and play iTunes - WOW she starts to really slow down to the point of it being unstable and totally unusable. - dual processor may take three times longer to complete the same tasks but the mouse moves as free as ever and the screen refreshes every time I click on an ICON. Non of the applications are multi-threaded or written to execute exclusively on a multi processor system. Which one is faster? Mac OS is UNIX, ok ok ok... A UNIX like operating system. Unix is 30% to 40% more efficient at running multiple processes then windows, you make the call. Brian Stewart ---------------------------------- CPU Clock Speed is a lot like Crank Horse Power It is not an accurate measurement of system performance. -- G-List is sponsored by <http://lowendmac.com/> and... 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