Depends on the screen actually)
If it's able to fill 4-8 tables, I can play it.
But for consentration the best is 1-4 ones I think.
Or 2-3 tables with differend games.
And of cos it depends on the type \ level of tables.
4 cash (no zoom) can play well, but 4 tournaments which started not simultaneously... will be difficult(
Cos You always have to remember which one is which and the level of stake.