"I have a modern computer."
Translation:Tôi có một cái máy tính hiện đại.
What is "máy vi tính"? I thought computer was "máy tính." Is this a regional difference?
Máy tính and máy vi tính can refer to the same thing (a computer). Overseas Vietnamese tend to use máy vi tính while in Vietnam people prefer máy tính. Máy = machine, vi = small/minute/minuscule, tính = to calculate. Máy tính can also mean a calculator so I personally differentiate the two by saying máy tính for calculator and máy vi tính for computer. You can also just say máy computer (especially overseas).
Melarish It's not the size of the machine but the calculations/computations. Computers use a lot more micro-calculations so there's that.
Technically, they are both computers nowadays on the inside. Those TI-83 calculators that the schools make us buy in the US are equipped with microprocessors that can run basic software. Now even the watches are computers…
I still do not understand why sometimes you need to have chiec or any other classifier, but other times you don't.
Not always. You would say chiếc đũa, chiếc xe etc. and you can say cái đũa but cái xe sounds weird.