Help Required - ZynFusion crashing on Studio One 4

[SimonCB]

Kia Ora,
I have been trying to run ZynFusion as a VST plugin through Studio One 4, however the process is unusually and painfully slow - often a simple function such as opening the mixing window will cause the entire program to stall and crash in some cases. ZynFusion appears to be taking up an unusually large amount of CPU usage within Studio One - I think part of the problem could be that it is only using one of the four cores on my CPU, but I have no idea how to check this. Does anyone have any ideas why this might be occurring and/or how to fix it?
For full specs, I'm running Windows 10 (64 bit) on an HP 15db0149-AU laptop, which has a Quad-Core CPU with 2Ghz base frequency, and I'm using Studio One 4 Artist from Presonus (with the VST extension). The above problem only happens within Studio One - if I run ZynFusion as a standalone app, everything runs fine.