If you mean Grade Point Average it does not mean a damn once you have published something. That is why it is so important to have a publication in an international journal. If you are the the 3rd year of your PhD and you have not published something and they are looking for some excuse to throw you out it is possible that they might try and use your CGPA against you.
I have an official IQ of 70 (NSW Department of Education) and I repeated Kindergarten. Neither have ever been held against me. I did get an Upper 2nd class honours not a first and that did hinder me in getting a scholarship for a PhD. The biggest handicap to my science career was my citizenship. I am Australian and I had no access to any other citizenship.