Hongkongers will normally get the following scores in IELTS.
Reading: 7-8.5
Listening: 7-8.5
Speaking: 5-6.5
Writing: 5-6.5
If you want to have 7 in every components, it is achievable by practising.
However, if you want to have 8 in every components, it is difficult to achieve in a short period of time, say 3-6months.
I think PTE is rather simple to get 79 in all components due to the following reasons:
On the contrary, listening in PTE is difficult. You probably won't be able to get 65 in 1st attempt. This part requires lots of practising!