Question

Just bought a new soundcard Focusrite Scarlett 6i6 2nd gen. (the same problem occurred with my old Tascam US144mk2)
When using my laptops default soundcard (windows audio. or ASIO4ALL) everything works fine
When I connect my interface, CPU starts spiking and cracking noises appear. Although when I switch back to laptops interface it's good again
Even when I set the buffer size alll the way to max. the same.
Even when I turn off the vst that is eating the most cpu, another one then comes up.

All drivers are up to date

 

Specs:
Asus GL752VW
i7-6700HQ
8GB ram
120GB SSD

Answer 1

Please try going into Studio One>Options>Audio Setup>Processing and set your Dropout Protection to "Maximum."  You may also want to try adjusting your Device Block Size.  Try setting the Device Block Size lower than 512. 

Since you are using a third party devices, and not Presonus devices, open Studio One > Options > Advanced > Services and disable "Presonus Hardware Support," and "Presonus Legacy Hardware Support." Restart Studio One and try again. 

 PreSonus has been seeing some issues come in with high CPU usage when using the Focusrite interfaces.  This issue has been logged internally for tracking.  You may want to reach out to Focusrite as well.  They may have an update available that resolves the issue or know of a possible workaround.