dual processor = faster rendering?

[doug shaffer]

Hi there -

If Macintosh OSX may 'take advantage' of dual processors, can I assume that

rendering speed (when using VW) will be increased if I purchase a

dual processor machine?

thanks for your help.

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d. s h a f f e r

a r c h i t e c t

[Guest]

Doug,

Unfortunately at this time VectorWorks does not support dual processors.

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Brian O

Nemetschek North America

Technical Support Specialist

[Guest]

The connection isn't quite that direct. Programs written for MacOS 9 may already, in fact, use both processors. For a single program to be able to use multiple processors simultaneously, that program must be able to divide the work it's doing into separate tasks that each processor can work on individually. These tasks are known as 'threads' or 'processes'.

MacOS 9 supports threads (as do MacOS 8 and even System 7, to some degree), but until recently there wasn't all that much incentive for developers to implement their applications in terms of threads. The ability to split code into multiple threads can help to organize and simplify code conceptually, but it also introduces a bunch of problems that don't exist in single-threaded applications. The How Stuff Works web site has a good discussion about these problems. Given all that, most developers didn't bother with adding threads support to their apps because nearly all Macs had only a single processor, and threads therefore didn't give any real speed advantage. (In fact, there's a little bit of overhead involved, which means that using threads might actually slow a program down on a single processor machine.)

Anyway, the big differences between MacOS 9 and MacOS X from a multiprocessing perspective are that MacOS X itself makes very good use of threads, and that it's able to schedule processes for both processors. MacOS 9 runs all applications on a single processor, even if a second processor is available, unless an app is threaded and therefore able to also use the second processor. (And even then, the 'main thread' runs on the first processor.) MacOS X will run applications on whichever processor happens to be available at the moment, and it's even possible that an app may find itself being switched between processors as it runs.

So where does that leave VectorWorks and RenderWorks? The currently shipping versions will run on only one processor even under MacOS X (RenderWorks really doesn't run as a seperate program, but as an extension to VectorWorks.) So they'll definitely have to be updated before they run on multiple processors. In other words, you won't see your model being rendered in half the time on a dual processor machine. That's not to say that it won't happen in a future update, however.

You'll certainly gain quite a bit of benefit from multiple processors and MacOS X, though, even with the current version of RenderWorks. You'll be able to start a render and then do other productive things, because your whole machine won't be tied up while the rendering is going on.