So this probably means that the cause of the spikes are the data products. If you look closely in the data product table of STEP, you can see that there are 3 science data products, and one "clear" data product to clear the memory, four in all. All get executed every second. The time between the largest spike and the first smaller spike is 300ms, exactly the time between the issuing of the "clear" DPS command and the "nominal science" DPS command in the PPSS table.
How can we confirm that?