OPC client Delay?

I’m working with a s7-1200 Siemens PLC, FactoryIO 2.5.1 licensed and MatrikonOPC.

I have a project with 200 IO tags aprox, most of them are boolean.

If i work directly with s7comm driver, Factory IO works. If I work with OPC driver, i have 1 second delays (or more) at Factory-PLC comms.
If i try opc with a few tags, everything works great.

Is factoryIO able to work with 200 tags with OPC? (I know the limit is 256)
Maybe the problem is the PLC? (S7-1200 series dont have a great CPU).

Somebody has tried this with a s7-1500 or more than one PLC?