I need a hosting company that provides shared or reseller hosting with a minimum of 2 complete CPU cores
It is best to check the forum of shared hosting and reseller offers, find some of the ones you like and contact them / research / read comments, etc.
But, why share or resell? Is it a matter of budget? You can get a VPS for not much more these days with a significantly higher use of resources and then you can not only use elements such as the W3TC add-on, but you can also configure Apache and PHP with the modules you want, the settings you want and all the resources. You are dedicated to yourself.