How many active users Opencart 2.0 can support?

Hello, we currently have a website hosted on a dual-core dedicated server with 128MB RAM on Hostgator and the website struggles after around 45 -50 active users according to Google analytics. I got someone to do some code optimization but still I can only reach about 80 active users and the website takes around 10 seconds to load. Is this normal or there are issues with the host?

We only have around 700 products on Journal 2 theme with only static banners and around 4 photos per product at around 110KB per photo.
I have now signed up a trial with A2 Webhost for another website on a 12-core dedicated server with SSD but not sure what to expect.

I hear people manage up to 1000 active users on a shared host. How is that possible and we are struggling with 50-80 AU ?
Your thoughts please...

Website www.g(p)a(b)ea.com Please substitute the (p) for an (r) and the (b) for an (f) without the brackets.

Default OpenCart queries are quite simple and can't cause any issues. It is absolutely impossible to say anything particular in such cases, because issue can be anywhere: with you server in general, with it configuration, with some queries and so on. The only way for you is to investigate this by yourself or with the help of server admin and hosting support.