Some interesting snippet taken from the Renoise Community:

  
(pysj @ Aug 30 2005, 12:51 AM)
 Perhaps it's possible to use EnergyXT in Renoise as a vst(i) distributer to different cores?
In eXT (beta) you choose which core to use in each vst plugin.

From XT forums about next upcoming version:
 

  
FOREIGN QUOTE
Is this functionnality (multicore support) available when eXT used as a plugin in an other sequencer ?

That would be interesting to turn a sequencer that does not support Dual core CPU into one that does.

Thanks,

Xavier

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It is possible to use multicore in VST version, you just have to load VSTs into the sequencer comp and use 
the sequencer comp as an instrument rack. Each track with its own VST must be set to "rec: manual" 
with its own midi receive/input channel.

jorgen
 

  
(pysj @ Aug 30 2005, 08:29 PM)

 I have tried the eXT beta in some other hosts, and it works.

But if I use Renoise and change the core of a vst(i) inside eXT, renoise will hang and crash.
But I dont have a real dual cpu system at the moment. 
So I have only tried this on a single hyperthreading core. 
So this crash might happend because Renoise dont support hyperthreading?
 

  
(keith303 @ Aug 31 2005, 02:59 PM)
pysj,
did you re-enable the second virtual CPU of your HT CPU for the renoise task?
you can do that from within taskmanager by rightclicking renoise.exe and checking the process affiliation.
renoise disables one of the two virtual CPUs by default to avoid problems with HT.
 

  
(pysj @ Aug 31 2005, 06:57 PM)
Cool.
It seems to work when both cpu's are enabled for Renoise.exe
I can see the load changing from one to another as I switch cores for vst(i)'s.
So this should work sweet for real dual cpu's.

eXT dont add much extra cpu usage for your plugins (about 1.2% on my 3.2GHz) per instance. 
And you can load as many vst(i)'s you want into each instance.