Pict
Thanks for the advice Mettelus I tried every setting but still no go maximum 6 Nebula instances as before.The audio interface is a  Cakewalk Sonar V-Studio 100  I don't think there could be a more compatible system  with Sonar than their own interface with their own ASIO driver. I think I'm out of luck trying to use Sonar with Nebula.Thanks again for the help.

That is actually a Roland interface and driver. While our name is on it, the only thing the Boston office really did was code the control surface plug-in. 
 
Edit: Just to clarify. There's no secrete sauce with the Cakewalk or Roland interfaces in regards to how they work in SONAR beyond control surface functionality. 

Is this Nebula 3 or Nebula 3 Pro?

The thread is getting pretty long. I saw the question asked but not answered on page one regarding the setting of the ThreadSchedulingModel in AUD.ini. The default value is 1. Setting it to 2 may be a better setting for a quad core processor.

Interested in these recent Reaper/Sonar comparisons, I tested the latest Reaper against Sonar X3d.
 
I used Sonar's TL-64 Tube Leveler plugin to test, since it strikes me as a pretty plain vanilla processor without a lot of weird tricks going on.
 
I put 64 instances in Reaper and in Sonar - 8 tracks of audio each with 8 instances.  I turned Reaper's "Anticipative FX processing" off, and Sonar's "Always stream Audio through FX" off (not that that should make any difference), with ThreadSchedulingModel in Sonar set to both 1 and 2.  The computer is a i7 3770 with an RME interface at 1024 samples.
 
I watched the Windows Task Manager as I played back in each program.  In Reaper the CPU usage hovered between 10 and 12 percent, while in Sonar it hovered between 10 and 16 percent, with a spike to 20 percent immediately on playback start.
 
It comes as no surprise to me that Sonar's CPU usage would be higher when performing the same task, because Sonar in general feels like a program with more overhead.  For one small example,the Reaper fx window hearkens back to Windows 98, while Sonar uses more pretty graphics.
 
Sonar is like a Subaru station wagon.  Reaper is a BMW diesel retrofitted to use biofuels.  To worry that a Subaru gets worse gas mileage than the biofuel-BMW is to ignore that the driving experience of the two cars is entirely different.

Isn't BMW generally considered the more luxurious driving experience over Subaru (or most Japanese cars)? :)

I drive a Subaru too. But I haven't used the Nebula plugin for years simply because it has always been a resource hog.

It's pretty easy to build a quad core Mac with good specs (i7 3770, 16GB RAM) for around a thousand bucks.
At least over here, I count in euros.
http://www.tonymacx86.com...ide-december-2013.html

Sanderxpander are you in the US?It costs more like $3000 in Europe for a new four core Apple and even on ebay $2000 for a used one which when compared to the price an equivalent horsepower Win machine that seems ridiculous to me.Anyway I can't afford anything like that at the moment so I'll just have to keep soldiering on with my old planned obsolescence junk

Keith Albright [Cakewalk]
I doubt all things are equal for a difference like that.
Perhaps SONAR is doing double precision processing and Reaper isn't?
Or, perhaps the audio buffer setting is 64 samples in SONAR but 256 in Reaper?
I never saw what the respective buffer settings were.  They'd have to be identical to even begin to try to draw a comparison.
 
 

Keith, he mentioned using identical buffers.

It's possible there's just something going on between Sonar and Nebula specifically. Reaper is known for being lighweight but as you say, this is quite a large difference. I haven't noticed differences this large with other plugs, and I'm sure you guys haven't either or you'd have been on it long ago.

Pict
Nebula 3 pro server

Does the software come with any support?
Have you contacted Acustica Audio to see if they can make any suggestions?
Have they tested their product with Sonar X3 (or even an older version of Sonar)?
Are other people reporting this problem with them - do they even know a problem exists?
Does Nebula have settings to tweak? If so, don't assume the same settings work between all DAWs.
 
Surely they want their software to work efficiently in any DAW or they risk losing customers.
 
If every VST was performing badly in Sonar then it might be fair to point a finger at Cakewalk. But this appears to be more of an isolated problem - maybe Nebula needs a tweak, not Sonar. (Didn't Waves just release an update late last year related to Sonar compatibility?)
 
Just sayin ...

Steve could you tell me which presets you used in Nebula?
 

It is not a mastering plugin.I suggest taking a look at january 2012 soundonsound article for a brief overview of the plugin and its possibilities or even better give it a try yourself there's a free version available.If you can make your recordings sound better why wouldn't you?Making music isn't the problem this is about getting your recordings to sound how you like them this plugin does that for me and many others it just doesn't perform well for me,I reiterate for me, in Sonar but it does in  a competitors product.I've spent much more money and time on Sonar and its addons than I have on its competitors product which runs this plugin well thereby allowing me to mix my previously recorded tracks unhampered .
 
          In my opinion it's not unreasonable to try and find it out why.It makes me wonder if maybe I'm spending money unwisely.People compare features between products all the time it's one of the main uses of the internet and when and if they try products and find greatly differing results I think it's important and interesting to know why,maybe others can learn from it. Isn't that the raison d'etre of a forum such as this?I'm not here to plug a plugin or a Sonar competitor I've tried everything I can think of to find a solution to get it to work with Sonar and every suggestion on this thread,nothing worked I think it's only natural to feel a bit disappointed but you know it's not exactly life threatening I'll simply use the other product. Thanks to all who contributed.

Thanks Steve I'll try them out on my system.

Steve using your combination in Sonar on 1 track on my machine uses less than a 3rd of the 1st core and about a 6th of the remaining 3 cores which is a very dramatic difference,but the ASIO buffer has to be raised to 1024 to eliminate pops completely.I think I know why,the kernel count is very low on most of those libraries but most of the libraries I'm using have much higher kernel counts from 6 to 11 compared to 1 kernel in 7 of the presets you used the  eq tape warmbus uses 11 the newman uses 5 and the Alexb uses 6 kernels it's when using these higher quality(more kernels) libraries that Sonar chokes at 6 but the other product doesn't until 16 instances with an ASIO buffer setting of 128.The more kernels the higher the processor demand.When I tried on my old duo core 3.06 GHz mac with Logic 9 only 4 instances could be used and  the 1st core was being used to the max and the 2nd core hardly touched.

codamedia
Does the software come with any support?
Have you contacted Acustica Audio to see if they can make any suggestions?
Have they tested their product with Sonar X3 (or even an older version of Sonar)?
Are other people reporting this problem with them - do they even know a problem exists?
Does Nebula have settings to tweak? If so, don't assume the same settings work between all DAWs.
 
Surely they want their software to work efficiently in any DAW or they risk losing customers.
 
If every VST was performing badly in Sonar then it might be fair to point a finger at Cakewalk. But this appears to be more of an isolated problem - maybe Nebula needs a tweak, not Sonar. (Didn't Waves just release an update late last year related to Sonar compatibility?)
 
Just sayin ...

+1. If you are seeing a drastic difference only with this plugin, your first line of action should be to contact that specific vendor and ask if they have done compatibility testing with SONAR. Perhaps they may be able to offer some support/workarounds regarding this. If they do indeed detect a compatibility issue with SONAR that requires our attention, ask them to contact us via this form and it will be investigated. We also provide free NFR's for companies to test their plugins with our products.
 
The developer support form to be used for compatibility reports is here:
www.cakewalk.com/About/email.aspx?EID=11