Pops when applying 3rd VST in rackspace

Im creating a rackspace and as soon as I add a 3rd VST im getting audio pops here and there…nothing on the first two…

any suggestions shoot!

What computer?
What OS version?
What plugin?
What happens when you try a different format (if available, AU or VST3)?

What sample rate and buffer size?

…and what’s the display of the CPU-load? (in Gig Performer, not of the general system)
See pos. 13
The main Gig Performer window