Any lightweight Windows tool for ad-hoc monitoring of switch-interface throughput?

Hi

Is anybody aware of a light-weight tool for Windows or MacOS, to monitor switch interface throughput?

Use case - This will be used ad-hoc, whilst on different customer sites (or at home), which I'd periodically point to a switch with SNMP, and it'll give me a graph showing throughput of an interface.

Note, I'm not looking for a full-blown NMS.

Thanks