Heard that 3.5k for fresh grad is not come just like that.. Those fresh grad won't have the retirement benefit or less retirement benefit as compared to previous batch employee.. 

Fresh grad student I think is harder to get into Petronas since mostly they take from their own sponsored student at Universiti Teknologi Petronas.. Every 6months more than 150++ Petronas sponsored graduated from UTP.. Heard from friends who intern at Petronas, the culture there is not good but think the culture may vary from dept and dept.. While UTP sponsored malays students tried to absorb into Petronas, most UTP sponsored chinese student tried to escape from being absorb by Petronas coz they aim for other oil n gas company or simply because does not like be in the Petronas culture..   

For the interview structure, it's the same for recruiting fresh grad and experienced candidate where need to undergo:-
1. Writing Test (More to ethical questions)
2. Numerial Test
3. Verbal Test (sort of english comprehension test)
4. Occupational Personality Questionaire (Personality test for them to know in detail about your personality)
5. Interview (Have 4 stages)
    5.1.  Background Check
    5.2  Case Study
    5.3  Competency based Interview
    5.4  Role Play

I agree on a thing.. The HR is slow..