Cacti not displaying right bandwith

[knifto]

I am monitoring a Zyxel GS2200-48 switch.
I created graphs, this is diplaying bandwith, but not right!

When I generate some traffic between hosts I get a throughput about 700Mbit, however the graph is not displaying this (only about 100Mbit p/s).

Where to start looking?

[cigamit]

You need to recreate them but select the dropdown for 64 Bit counters.

[knifto]

Thanks, seems that this worked.
How can I determine which counters to use?