After it gets about 5 minutes into the defrag its gets super heavy on one CPU. And I do have antivirus. It happens more often with larger files but with small files it stays at 15%.
Even with the fastest cpu's on the market Defraggler will run only one out of how many cpu cores you have at 100% usage.
If Piriform were to spread the load over at least two CPU cores (Preferably 4) It would half the time it takes to defrag!
I hope Piriform takes this idea into consideration!