If we do have a speed problem, then Activity Monitor (which we all have in our Utilities folder) is our friend. He demonstrated how a well written program uses the processor and then releases it for others when it's not needed and Activity monitor shows us this happening. If however one of your programs is hogging the processor, it will be shown in Activity Monitor and can be investigated. He showed us a program which he'd written especially to hog the processor and how Mac OS still copes but the machine will get hot, slow down and its fans come on. Similar information is shown for memory usage, the amount of RAM swapped out to temporary storage on the hard disc being of particular relevance.
After the coffee break we had the usual Q&A session covering a connection issue for an iPad and strange behaviour with an external disc used for time Machine.