Apple Logic Pro /LogicExpress Discussion

> Hey we're both right. For mundane tasks, the dual 1.8 is 
> probably exactly the same speed as the single 1.8. It won't 
> open a file faster, or redraw the screen faster, or respond 
> to a mouse click any faster at all. But when it comes to 
> processor-demanding task, thats where the 2nd processor comes 
> into play In the case of a Photoshop file, its fairly easy to 
> divide the task into two or more pieces to do separately. 
> With audio I'm not so sure. Maybe bounces are similar. Or 
> maybe if its smart, it will put some soft synths and plugs on 
> each processor.
> 
> Suppose you invite a friend to help you cook dinner - to bake 
> a cake and wait an hour while its in the oven is going to 
> save any time. But if you were making some complicated 
> dishes, maybe the friend cuts some vegetables while you make 
> a soup, and so forth, and you can both access the kitchen 
> counter when you need it. Depending on the dish it might be 
> almost the same as by yourself or maybe almost twice as fast.

I do think we are more or less on the same page, but I think when you are
describing getting 2x performance out of the 2 CPUs, you are describing a
technical Nirvana that simply doesn't exist in reality. If those two CPUs
have all of the code in cache and all of the data in cache, then you can get
exactly 2X performance. As soon as you need to access resources of any type,
RAM included, the performance goes down substantially. In the case of RAM,
yes, technically the CPU could be doing something worthwhile while the other
CPU is accessing memory, but it is unlikely in the extreme. The memory runs
at 400 MHz and it is CL 3 RAM which means it takes three clock cycles from
request to data available. If the 2nd CPU needs to access the RAM at that
same time, it has to wait for those full 3 clock ticks. Could it do
something else while waiting? Probably not. The decision to do something
else would, itself, consume CPU time and I can't imagine it doing anything
other than waiting. Finally, I suspect that memory accesses are likely to
come in bursts rather than a word at a time, for instance, when applying
effects to an audio track, the code is probably going to work with a chunk
of that audio at a time - 16 words, 32 words, maybe 64 words - but something
greater than a single word. Once loaded the CPU can likely perform its task
without accessing memory again until the next chunk of audio is needed.

Anyway, yes, in theory, I see your point. However, in practice, I don't
think it will ever be realized.

Kamm