Steve in Sonar with only one instance of Nebula running Sonars CPU monitor shows a low usage spread evenly across all core with 6 instances running the 1st core is in the red with the remaining cores averaging about 50% moving the mouse stops playback.In Reaper one instance of Nebula is 6% with 6 instances only 12%.
              In windows resource monitor running 6 Nebula instances the 1st core in Reaper averages about 20% with the remaining cores using about 15%,10%,and 8% respectively compared to Sonar which shows 55% across all cores on average.There is no stopping of playback in Reaper or glitching at all with any mouse movement even when Reaper is almost at max with 16 Nebula instances (96%) there's no glitch or playback stop.Reaper averages 11% average CPU use on the windows resource monitor compared to Sonar at 35% average with same number of Nebula instances and Sonar constantly spikes up to 100% stopping playback.

Maybe modifying ExtraPluginBufs in AUD.ini will help. If I had to pick a value, try setting to 32
I am guessing this is a 64bit version of Nebula running on a 64bit version of SONAR. I do not have a 64bit version of Nebula to test and did not install the 32bit version on my current machine.

Scook and Reza thanks for the info I'll try the AUD.ini adjustment.As I've said before I've been mainly a Logic user and before that Creator and Notator I really wish that Logic was still available for the PC the notation is excellent,the 90 screensets are great I feel really limited with 10 if only Macs weren't such a ripoff (imo).
    I would love to get Sonar running as smoothly as some of the people on here have it running.I didn't like the interface of the pre X series of Sonar and I thought that with Sonar adopting a more Logic like GUI it would be easier for me to use it but sadly for me it hasn't fulfilled my expectations I really get annoyed having to tweak preferences and registry entries etc but after investing time and money on it I don't want to throw it down the pan but I'm getting close.

I wonder if up sampling, down sampling, filtering and dither between every instance might explain the difference.

Perhaps disabling 64 bit engine might help?

pan laws?

Whenever I encounter CPU spikes/usage/dropouts I always look to my ASIO buffer settings. I am also a frequent user of two different DAW's, and a single universal buffer setting does not always work between them. If DAW 1 wants the buffers set to "yyy", DAW 2 might be happier at "zzz". There are no rules, just take the time to optimize them for each DAW.
 
I also only run lower buffers during tracking - and only if I need to use input monitoring. When I go into mix mode - I raise the buffers to allow more CPU for plugins.
 
Just my 2 cents...

lawp
nebula is a cpu-hungry plug fo' sho'... how are you using the instances? if they're all on the same channel, that channel is all going to a single core i believe

 
Does anyone know for sure if Sonar works like this?
 

Pict
All of this on one track of audio.

 
If "LAWP" is correct and you are testing with a single track, maybe this is the source of the difference.
 
Can you duplicate the track and apply Nebula on several different tracks/channels to see if performance is improved? I'm not saying that is a solution - I'm just saying it might go a long way in explaining why there is such a discrepancy.
 

similar thread http://forum.cakewalk.com/FindPost/2943488

Yikes... that thread again...
 
I remember someone posting they used Ozone 5 on every track a couple months ago, and someone responded that they were impressed. I assume this is one of the more "CPU hungry" plugs and I just got it a few weeks ago. I just started piling them on an audio track and assigning them each a different preset master setting (i.e. processing audio actively). They started to gain stage each other, so I had to keep lowering inputs/monitor settings. I got bored with this at 10 instances, play it, and CPU is running 6%. This is definitely not a "real-world" application of plug-in use, and if I owned a plug that consumed my machine, I would kick it to the curb quicker than last week's news.
 
Edit: I just closed the project (left X3 open) and CPU dropped to 2% and freed 1GB of RAM.

mettelus
Yikes... that thread again...
 
I remember someone posting they used Ozone 5 on every track a couple months ago, and someone responded that they were impressed. I assume this is one of the more "CPU hungry" plugs and I just got it a few weeks ago. I just started piling them on an audio track and assigning them each a different preset master setting (i.e. processing audio actively). They started to gain stage each other, so I had to keep lowering inputs/monitor settings. I got bored with this at 10 instances, play it, and CPU is running 6%. This is definitely not a "real-world" application of plug-in use, and if I owned a plug that consumed my machine, I would kick it to the curb quicker than last week's news.
 
Edit: I just closed the project (left X3 open) and CPU dropped to 2% and freed 1GB of RAM.

It's gonna sound sarcastic, and it's NOT meant to, but I don't understand your point in relation to the OP?

Seth Kellogg [Cakewalk]

Sanderxpander
It's gonna sound sarcastic, and it's NOT meant to, but I don't understand your point in relation to the OP?

SONAR is a sample accurate application. Reaper is not sample accurate in it's default configuration. Sample accuracy adds higher demands on system resources.

Testing Reaper in one of the sample accurate modes may show similar results to SONAR's baseline. 
 

Sorry, we cross-posted, I meant Mettelus and have edited my post to reflect that. Thanks for your explanation though!

Scook a link to that gearslutz test was posted in this thread earlier thanks.It's not a general comparison of Sonar to Reaper that I'm talking about it's how it handles this specific plugin that bothers me I would like it to be possible to mix down with the same amount of instances of Nebula in Sonar as in Reaper I would like to be able to do all my work in Sonar from tracking to final mix using this specific plugin and if I can't get that to work as I would like then it's either track in Sonar and final mix in Reaper or ditch Sonar and move over to Reaper which I have already paid for anyway.It would be ideal for me to be able to use only Sonar as I've paid for the melodyne upgrade,Karl's videos,prochannel modules etc.
 
              I've been patient with various problems through earlier versions of Sonar and I know all DAWs have their issues but I like the sound of Nebulas libraries and 6 instances just won't allow me to use it as I want.Sonar could run a billion instances of some other plugin compared to Reaper or another DAW but it's Nebula I want to use and Sonar feature rich as it is just doesn't seem to cooperate well with it figuring out why and finding a solution is the only agenda I have.When it comes to other issues I've had with Sonar I can usually find a workaround on my own this is only the 2nd time I've  asked for help on the forum the 1st time I solved the issue myself and I don't like asking for help but Nebula is a product I intend to keep using and using two conceptually different DAWs to get the job done is not my idea of smooth workflow as I'm sure almost anyone here would agree.

I've tested Reaper in sample accurate mode and it performs the same as before with no discernible difference.

The latency/IO buffers are a system specific thing that has a "sweet spot" that is system dependent. I just ran back through the thread quick but did not see what driver mode, and audio interface you are using. These also play into the overall picture. Realize that "maxed out" buffers can be just as bad as too small.
 
As far as finding the sweet spot for your system, it is good to take a fairly intensive project (the X3 demo project is a good choice) and use that for tailoring these.
 
ASIO mode with drivers specific to your interface are highly preferred. WDM mode is a best second, and anything other than these two tend to cause issues for most people (in general).
 
Start with the ASIO buffer at 128 (Preferences->Audio->Driver Settings->ASIO Panel...), and I/O buffers at 512 (Advanced Mode: Preferences->Audio->Synch and Caching)

1. Set preferred audio buffer.
2. Start playback.
3. If it drops out or other issues adjust I/O buffers in steps of 256.
4. Repeat steps 2 & 3. Try adjusting buffers both up and down until happy. 256 jumps should do.
5. If after trying all sizes up to 1024 you still have issues go back to step 1 and increase audio buffer to the next available setting (these are often "locked" to something like 128, 192, 256, 384, 512, 768, 1024, 2048).
6. Repeat as necessary until you find the "magic" combination for your setup.

   The default settings of 128/512 usually fit most scenarios fairly decently.
 
   As mentioned above, the driver mode you are using, and audio interface can also make a massive impact on "system," depending what they are.
 
 

I wish I had a solution for you. I am not familiar with Nebula (at all), there was a post by bitflipper that might be helpful as far as work flow beyond this point.
 
There are a lot of folks in the forums who know plug-ins extremely well, and could probably suggest a comparable alternative for you if you are willing to go that route.