Should I upgrade to ZorinOS Core?

I currently use ZorinOS 16.1 Lite but I want to upgrade to Core.

But I’m not sure if my PC will run as fast as with Lite.

My specs:

• Intel Core 2 Quad Q9450 with 2,66 Ghz
• 6 GB of DDR3 RAM.
• 128GB SSD and 1 TB HDD.

Should I upgrade to Core? And will my performance remain the same?

It should run fine on Core. I would not expect the performance to be exactly the same, but it should still be pretty good. 2.67ghz is not bad.
However, switching to Core is not an Upgrade.

How much performance I will lose when I switch to Core?

It is hard to say. Experiences can vary, depending on how you use the system, what apps you run, etc.
Why not just boot as Try Zorin and test it out?

I use it for basic office, coding and some games like Minecraft or GTA SA