Shared hosting vs VPS

We had a shared hosting solution erlyer.

However wee felt this started to go slow.

we desided to change to VPS server and the hosting company said this should boots site experience.

however this is not the case, the site is slower then ever, is there someone who knows how to optimize server/cs-cart so it speeds upp alot ?

our shop is

I have never managed my own server and is not wery familier with this.