It's most likely the monitoring of the scheduled task, it checks every second whether the task is created, and whether it's disabled. To do this it runs schtasks on Vista upwards, and JT.exe on XP.
BE1 recently brought this to my attention, and I made some alterations, one of them being to increase the time between the above checks.
If you minimise it to the tray, then the checking is disabled, and should lower CPU usage, does this happen?
It also loads the stats every minute, but this takes mere milliseconds, lowest I've seen on my slow old works PC is 3 milliseconds, but averages around 10.
If you have the settings tab open on the directories tab, then it checks if the folders exist every second.
There's nothing else going on to use CPU cycles really.
Mine flicks between 0 and 1% CPU usage, but then my CPU is a quad core running at 4Ghz with a nice fast SSD
but I suspect that the relevant code for SCHTASKS or JT.EXE stays in memory so is not loaded from disk every time it's run.
I'm sure that Roseway is a much better programmer than me, I haven't really programmed since I used to write machine code on the ZX Spectrum, but I'm learning fairly quickly now and may well be able to optimise some code.
If I let my brother look at my code, I'm sure he'll rip it to bits, he's a perfectionist and programming is his career.