Hey there,
i have 14 years if experience with music production and audio design. I recommend you to use a different program for audio purposes such as cubase.
but it sounds like your system has not enough RAM. For Audio production you will need at least 8gb Ram. One of my first systems was like that
CPU. Intel i5 3750k
GPU Build in From Mainboard
8GB Ram
Audio Interface Focusrite Safire USB6
I was able to do audio mixes with more than 80 audio tracks in a project. And produce music with about 20 VSTi’s.
But it always depends on the vsti you are using. A nexus2 or eletrax won’t need that much RAM like an Kontakt Library.
So when your PC or the program crushes at a specific amount of VSTis I think it’s a RAM problem. But check your CPU as well. If its similar to the i5 3570k you should be good and get more RAM. but always check that you are using the 64bit version of the program and windows. otherwise the program won’t use more than 4gb ram no matter how much ram u got. So get the 64bit versions and 8-16 GB RAM.
Check the Audio Buffer Length. When the sound starts to crack it means your CPU is to slow. u can bypass that with increasing the audio buffer length.
Cheers
Sean