@AymzFN
The only things that come to mind are to make sure you are fully up to date. Manually force Windows updates to search, even if it says its up to date.
There might also be a service starting up in the back ground every half hour that's taking up resources momentarily and causing the freeze. You would have to open the Task Manager and keep an eye on whats opening at that time.
Control/Alt/Delete will open the task manager. Click once on the CPU Column to highlight it and arrange the percentages from highest to lowest. When a service pops up at the moment of the freeze that you think is the culprit, you can disable it.