It depends, entirely, on if the programs you are going to be using are optimized for dual cpus.
As far as I know, and you\'ll want to double check this, none of the NI based players or plugins are optmized for dual cpu machines.
My guess is..you\'d get more performance out of using a faster single cpu...than you would to add another cpu of the same speed you have....unless...most of the heavy cpu hitting software you use is optimized for multi-cpus.
So, check to see if the sequencing software you are using is optimized for mult-cpu system..and as well..any plugins you have. Just having your seq multi cpu aware..can benefit you even if some of your plugs don\'t. (ie..keeping your screen redraws snappy even under heavy loads...faster processing of audio files/bouncing..etc)
Don\'t know what sequencers, etc. you\'re running but I\'ll give you my experience.
I\'m running XP on a dual Athlon MP with Sonar, Kontakt, etc.
Sonar has added improved support for multiprocessor boxes and will give you significant performance improvements with this functionality.
Kontakt is not multiprocessor enabled which may or may not be a problem.
If I only run one instance of Kontakt everything works for me (I\'ve heard of other users getting noise, but I think they were mainly P4 users utilizing hyperthreading.)
Where I get into trouble is when I run multiple instances of Kontakt. Each instance will try and respond the others controller automation for a given channel. In other words, cc -1 messages sent to Kontak1 channel 1 will be applied to Kontakt2 channel 1 as well.
Disabling the multiprocessor engine in Sonar fixes the problem, but then Sonar effectively uses only one cpu.
Of course this is all moot if you\'re running Cubase [img]/ubbthreads/images/graemlins/grin.gif[/img]
The one major advantage of dual CPUs in this instance is that the system is much less likely to freeze up on you if you max out the processor.
You\'ll get 50% increase power with second CPU. Plus, much faster sreen redraw. Plus, the more you closer to the CPU meter peak, the less problems will be encountered. I have 2 AthlonMP processors with nuendo and have to say i haven\'t seen more powerful machine (comparing to those with single cpu).