Does the engine oil affect the top speed of each gear

I have an R15v3 with 4.5km mileage, just recently I had no choice but to use semi synthetic oil because the shop I bought the oil from gave the wrong product, now I feel that my engine "roars" too early on each gears compared from before when I was still using the fully synthetic one.

My questions are:

1. Is it a bad thing that my engine roars too early? (Or is it normal given my current mileage?)
2. Should I change my engine oil right away? (I live in Philippines where it gets 32-38 hot, also there’s significant traffic during daily commute)