It's Excel 365, windows 10 and nothing wrong with the computer, it's pretty fast usually with 8GB Ram (1.8 GHZ) processor. Nothing is in the background and even if other applications like chrome even closed during the time. And the test I did with 5000 rows x 30 columns, it took just 5 seconds but with the heavier file it takes way more time.

Just for your information, the file is quite huge it has a size of 165 MB and I don't have any clue why that's so huge with that simple text entries, without any formula and conditional formatting and perhaps that's the reason it's that slow. Thank you