hello people
why is renoise going grazy if i juse more than 3 vst instruments
i hear a lots of ticks etc etc and my cpu meter is going to almost 90%
i have a good computer i think its a p4 1.5 whit 576mb memory
and a soundblaster cart
how nows the problem 
greetings dr.badvibes
It depends on the type of VST instrument.
When using synths, then a lot of cpu resources go to realtime calculation.
Samplers don’t have that much impact upon CPU resources but the more embedded effects they have (and you use) also raise the cpu consumption.
576MB of memory is not much if you use sampler software and load in an massive amount of samples. This will cause the the operating system to start moving data to your swap / page-file and when this data is required to be moved to your RAM, this will cause jerking sound and cluttering.
The disk-transfer will in 90% of all cases be too slow to the required transfer rate from the databus to the soundcard.
Which soundblaster card do you have?
1.5Ghz is enough power to make Renoise work decent with internal samples (using RNI instruments). When using VST instruments, you should also watch the required system specs mentioned at the developers who created the VST instrument or VST device.
Add all these minimum requirements in one sum and devide the whole by the amount of devices used plus ofcourse Renoise and the average cpu power coming from that devision will give you an indication of what cpu you really need to be able to create a song that can sound flawless in Renoise.
Since not all clicky or choking sound behaviours relate to cpu resource shortage:
I would recommend an average amount of around 1GB system-memory if you don’t want the page-file to be acquired during your Renoise sessions, but then again this also depends on how large amount of samples you would like to use.
If there is no possibility to upgrade your system in this manner, other tricks that can be applied:Use “Render To Sample” upon tracks that use heavy cpu instensive VSTI’s and mute the real VSTI track temporary, but play the rendered sample in a different track, just to have the reference of how this instrument plays along with the rest of the song;
In this case the VSTI won’t be used (the cpu resources are saved) and you can use other instruments along the rendered portions.
When you would like to render your song to the end-result, you mute all tracks that use the rendered samples and unmute the VSTI tracks and you render using the “real VSTI compatability” option to have clean and none-choking output.
If RAM becomes very low due to the rendered sample stuff, delete some of your rendered samples to avoid the page file being used.