One processor at a time?

i belive that one processor handles current foreground programs, and one handles system idle processes and background programs.

believo said:

I've heard that when working in a program, even though it's a multi-processor supported program, you are only using one processor at a time on that particular program. Is this true?

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Depends on the number of THREADS that the program creates.

The OS manages threads, which can be run on either CPU (and in some cases the GPU.)

believo said:

I've also heard that while the G5 dual 2.0s have 8 ram slots. Four are used for one processor and four for the other. Is this true?

thanks!

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Nope all the memory is hooked to Memory Controller and shared by both CPUs, it's not hooked to the CPUs -- what you are talking about would be for a NUMA architecture system, which we don't have yet (because there are NO integrated memory controllers.)

Thats part of AMD's architecture.

believo said:

for instance photoshop or final cut HD, do u know about these particular programs?

thanks

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Check out http://www.barefeats.com

Considering some of the "filters" run twice as fast on duals as they do on singles would lead one to think that they take advantage of the 2nd CPU.

Plus photoshop is one of the oldest multi-cpu capable applications on the Mac.

believo said:

for instance photoshop or final cut HD, do u know about these particular programs?

thanks

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Both of these programs are fairly heavily multithreaded. So are most 3D programs, Omniweb, and many others. These programs will use both processors at the same time. Some other programs will only use one, and the other processor will be used for other tasks running at the same time (and there are always other tasks running).

Trace the traces from the RAM slots to the controller, then from the controller all the way back to the CPU, there's one way you can tell that, but seriously, it all runs on the same memory. On a multi-cpu system, 1 cpu won't handle a certain number of slots of memory, that'd just make the system sluggish. Especially if it was using the processor the memory was hooked up to the most. Nothing would honestly run that fast. OS X, would probably take 10 more seconds to load, Photoshop about 12 more seconds, and yeah just think of it like that. Like I said, you want to see it for yourself, trace the traces back and forth.

believo said:

I've heard that when working in a program, even though it's a multi-processor supported program, you are only using one processor at a time on that particular program. Is this true?

I've also heard that while the G5 dual 2.0s have 8 ram slots. Four are used for one processor and four for the other. Is this true?

thanks!

Click to expand...

One thing's for sure, whatever your source was for the information stated above should not be viewed as authoritative ;-)

DanTekGeek said:

i belive that one processor handles current foreground programs, and one handles system idle processes and background programs.

Click to expand...

no

Catfish_Man said:

Both of these programs are fairly heavily multithreaded. So are most 3D programs, Omniweb, and many others. These programs will use both processors at the same time. Some other programs will only use one, and the other processor will be used for other tasks running at the same time (and there are always other tasks running).

Click to expand...

Yeah, most pro apps will be multi-threaded but you won't see it in Safari or Mail anytime soon.

The real benefit for general use will be when ALL of the OS is multi-threaded. Some parts of OS X are not yet.