These are not the same
To get a good score in IELTS writing and speaking, you need to show that you can use complex sentences with a linker. Some students get confused with EVEN IF and EVEN THOUGH and then they decide NOT to use them :( But you should learn how to use them and try :)
Even if means whether ... or not
It doesn't matter if / whether I had $2000, I still wouldn't buy that suit.
It doesn't matter if / whether you were the only man available, I still wouldn't marry you.
Even though means despite. It's almost the same as Although and Though, but with more emphasis.
AND IN IELTS WRITING?
You can use these linkers in the conclusion to a Task 2 essay.