I'm launching a web app, which is currently in beta running on a "Lite" VPN account from my hosting provider. It has 2 cores and 1GB RAM.
I have only about 10 users now but Im considering whether I should just boost up the server to the "Pro" setup for $100/month, being 8 cores and 3GB RAM.
Aside from handling more LOAD..as that is not really needed for my whole 10 users, will it actually make my app any faster going from 2 to 8 cores? It's a web api written written mostly using async/await (C#) (IIS 8.5 on Win Server).
Will it have any noticable difference for my users?
I think it depends on what is the resource utilization on your current system. Are you noticing CPU/Memory/Disk-IO/Network saturation or frequent spikes ? If yes then you will benefit with faster machine, otherwise I don't think it will make any noticeable difference. You should be able to see the difference by monitoring site latency from your webserver access log.
The question is if the app scales well on multiple cores. I.e. is one user connecting to the server able to saturate all cores. Since we know little about the app itself, you would have to provide more detail, or do some tests with some load graph.