Originally Posted by: Seventh Sam 
Originally Posted by: DANIELE-ES
There's something wrong I don't catch. Did you have some busses in the test you did?
I fired up a new test project. Set up a VEP instance of 16 kontakts all playing a bunch of MIDI nonsense, feedback routed, etc. and this time splitting their output into two separate buses. Tracks 1-8 went to BUS 1, while 9-16 went to BUS 2. The RT CPU was consistently idling around 2-3% and at 7% during playback.
Then I set up 16 tracks of individual kontakt instances playing the exact same MIDI, but no VEP, feedback routing, etc. Same bussing set-up. With this, the RT CPU idled around 5% and went to 10% during playback.
I'm stumped, dude. I tried moving the BUSES around, disabling feedback routing, etc. All my results were consistent - the VEP set-up, even with feedback routing, was more CPU efficient, RT and non-RT, than the non-VEP set-up.
I don't know if it's going to be any help, but I've attached the project file.
At this point, I'm pretty convinced there's something in your project itself that's causing an issue. I know it's a huge PITA, but have you tried just setting up a big (or semi-big) template using VEP and feedback routing the way you normally would for a project? Have you seen if this RT CPU strangeness is happening with other projects of yours? It could just be that you're mixing older settings with newer technology and there are compatability issues. I could, of course, have no idea what I'm talking about, but it's worth a shot.
I do hope this works out...
- Sam
EDIT: My VEP buffer is set at 2, fwiw and latency is 128 on my audio interface
Ok, I used your project to test it out and I have max 3% of RT CPU exactly as you, now try your project with a little update and let me know how much your RT goes up.
In your project, the updated version (but the same would be with the original one) if I disable feedback routing I get a RT at 0%, if I enable it I get a RT at 12-13%. Not too much in general but too much if you think about bigger templates.
I used three instances now and I expanded the audio channels from 12 to 64 (the maximum allowed by Reaper) and the RT cpu goes UP, I use always 64 channels because I don't want to create to much instances. With all the tracks disabled I have the same problem, this is because even if I put offline my FXs sends remain active and there is where the problem is. If I mute my tracks I see a big improvement.
There's really nothing I can do, it is the feedback routing itself that is causing the issue, a massive performance drop, if I disable it or if I delete all sends RT drop down from 50-60% to 10% (there is still something going on in my template but I think is not so important at this point).
Conclusion:
- I cannot use Event Input;
- I cannot use Midi;
- I don't want to double my tracks.
I cannot use VEP, I think that Reaper users should be informed of this. This is not a VSL fault obviously but untill the Reaper Devs will go to work on this (and who knows when) VEP is useless in these conditions.
I hope I will find VEP useful in the future, until that it is a waste of money for me unfortunately. Well I think I had to try to find all this.
EDIT
With a buffer at 128 on my ASIO interface I get a RT at 5% with the original project and at 17% with the updated one. I did the previous test with a buffer at 512. It is a pretty strange behavior since my CPU is faster than yours but here it seems slower. Anyway it could depend on a huge amount of factors (I already have AV disabled and so on...). The conclusion doesn't change then, even if my results are sligthly different from yours disable FR solves the issue but kills VEP for me.