Is the server JavaScript runtime significantly slower?
@SKFrozenCloud I’m afraid your question needs a lot more detail if you want a useful answer. Slower than what exactly? Slower at handling what specific workload? What counts as “significantly”? The more information you can provide, the more we can try to help. 
In any case I suspect the best answer will be: benchmark the runtime, with your custom code loaded into it, and hit it with the exact workload you expect it to handle in a production setting. This will give you the best insight into how it will behave in the real world.